diff --git a/doc.go b/doc.go
index 06253f4e..45138cb1 100644
--- a/doc.go
+++ b/doc.go
@@ -315,7 +315,7 @@ stale log entries:
 	rafthttp package.
 
 	'MsgApp' contains log entries to replicate. A leader calls bcastAppend,
-	which calls sendAppend, which sends soon-to-be-replicated logs in 'MsgApp'
+	which calls maybeSendAppend, which sends soon-to-be-replicated logs in 'MsgApp'
 	type. When 'MsgApp' is passed to candidate's Step method, candidate reverts
 	back to follower, because it indicates that there is a valid leader sending
 	'MsgApp' messages. Candidate and follower respond to this message in
@@ -353,8 +353,8 @@ stale log entries:
 
 	'MsgSnap' requests to install a snapshot message. When a node has just
 	become a leader or the leader receives 'MsgProp' message, it calls
-	'bcastAppend' method, which then calls 'sendAppend' method to each
-	follower. In 'sendAppend', if a leader fails to get term or entries,
+	'bcastAppend' method, which then calls 'maybeSendAppend' method to each
+	follower. In 'maybeSendAppend', if a leader fails to get term or entries,
 	the leader requests snapshot by sending 'MsgSnap' type message.
 
 	'MsgSnapStatus' tells the result of snapshot install message. When a
@@ -376,7 +376,7 @@ stale log entries:
 	'MsgHeartbeatResp' is a response to 'MsgHeartbeat'. When 'MsgHeartbeatResp'
 	is passed to leader's Step method, the leader knows which follower
 	responded. And only when the leader's last committed index is greater than
-	follower's Match index, the leader runs 'sendAppend` method.
+	follower's Match index, the leader runs 'maybeSendAppend` method.
 
 	'MsgUnreachable' tells that request(message) wasn't delivered. When
 	'MsgUnreachable' is passed to leader's Step method, the leader discovers
diff --git a/raft.go b/raft.go
index 7f591f26..70c209f5 100644
--- a/raft.go
+++ b/raft.go
@@ -218,6 +218,21 @@ type Config struct {
 	// throughput limit of 10 MB/s for this group. With RTT of 400ms, this drops
 	// to 2.5 MB/s. See Little's law to understand the maths behind.
 	MaxInflightBytes uint64
+	// DisableEagerAppends makes raft hold off constructing log append messages in
+	// response to Step() calls. The messages can be collected via a separate
+	// MessagesTo method.
+	//
+	// This way, the application has better control when raft may call Storage
+	// methods and allocate memory for entries and messages.
+	//
+	// Setting this to true also improves batching: messages are constructed on
+	// demand, and tend to contain more entries. The application can control the
+	// latency/throughput trade-off by collecting messages more or less
+	// frequently.
+	//
+	// With this setting set to false, messages are constructed eagerly in Step()
+	// calls, and typically will consist of a single / few entries.
+	DisableEagerAppends bool
 
 	// CheckQuorum specifies if the leader should check quorum activity. Leader
 	// steps down when quorum is not active for an electionTimeout.
@@ -335,6 +350,12 @@ func (c *Config) validate() error {
 	return nil
 }
 
+type msgBuf []pb.Message
+
+func (mb *msgBuf) append(m pb.Message) {
+	*(*[]pb.Message)(mb) = append(*(*[]pb.Message)(mb), m)
+}
+
 type raft struct {
 	id uint64
 
@@ -360,7 +381,7 @@ type raft struct {
 	// other nodes.
 	//
 	// Messages in this list must target other nodes.
-	msgs []pb.Message
+	msgs msgBuf
 	// msgsAfterAppend contains the list of messages that should be sent after
 	// the accumulated unstable state (e.g. term, vote, []entry, and snapshot)
 	// has been persisted to durable storage. This includes waiting for any
@@ -372,6 +393,10 @@ type raft struct {
 	// Messages in this list have the type MsgAppResp, MsgVoteResp, or
 	// MsgPreVoteResp. See the comment in raft.send for details.
 	msgsAfterAppend []pb.Message
+	// disableEagerAppends instructs append message construction and sending until
+	// the Ready() call. This improves batching and allows better resource
+	// allocation control by the application.
+	disableEagerAppends bool
 
 	// the leader id
 	lead uint64
@@ -447,6 +472,7 @@ func newRaft(c *Config) *raft {
 		maxMsgSize:                  entryEncodingSize(c.MaxSizePerMsg),
 		maxUncommittedSize:          entryPayloadSize(c.MaxUncommittedEntriesSize),
 		trk:                         tracker.MakeProgressTracker(c.MaxInflightMsgs, c.MaxInflightBytes),
+		disableEagerAppends:         c.DisableEagerAppends,
 		electionTimeout:             c.ElectionTick,
 		heartbeatTimeout:            c.HeartbeatTick,
 		logger:                      c.Logger,
@@ -502,6 +528,11 @@ func (r *raft) hardState() pb.HardState {
 // send schedules persisting state to a stable storage and AFTER that
 // sending the message (as part of next Ready message processing).
 func (r *raft) send(m pb.Message) {
+	r.sendTo(&r.msgs, m)
+}
+
+// sendTo prepares the given message, and puts it to the output messages buffer.
+func (r *raft) sendTo(buf *msgBuf, m pb.Message) {
 	if m.From == None {
 		m.From = r.id
 	}
@@ -584,24 +615,51 @@ func (r *raft) send(m pb.Message) {
 		if m.To == r.id {
 			r.logger.Panicf("message should not be self-addressed when sending %s", m.Type)
 		}
-		r.msgs = append(r.msgs, m)
+		buf.append(m)
 	}
 }
 
-// sendAppend sends an append RPC with new entries (if any) and the
-// current commit index to the given peer.
-func (r *raft) sendAppend(to uint64) {
-	r.maybeSendAppend(to, true)
+func (r *raft) getMessages(to uint64, fc FlowControl, buffer []pb.Message) []pb.Message {
+	if to == r.id {
+		// TODO(pav-kv): async log storage writes should go through this path.
+		return buffer
+	}
+	pr := r.trk.Progress[to]
+	buf := msgBuf(buffer)
+	for r.maybeSendAppendBuf(to, pr, &buf) {
+	}
+	return buf
 }
 
-// maybeSendAppend sends an append RPC with new entries to the given peer,
-// if necessary. Returns true if a message was sent. The sendIfEmpty
-// argument controls whether messages with no entries will be sent
-// ("empty" messages are useful to convey updated Commit indexes, but
-// are undesirable when we're sending multiple messages in a batch).
-func (r *raft) maybeSendAppend(to uint64, sendIfEmpty bool) bool {
-	pr := r.trk.Progress[to]
-	if pr.IsPaused() {
+// maybeSendAppend sends an append RPC with log entries (if any) that are not
+// yet known to be replicated in the given peer's log, as well as the current
+// commit index. Usually it sends a MsgApp message, but in some cases (e.g. the
+// log has been compacted) it can send a MsgSnap.
+//
+// In some cases, the MsgApp message can have zero entries, and yet being sent.
+// When the follower log is not fully up-to-date, we must send a MsgApp
+// periodically so that eventually the flow is either accepted or rejected. Not
+// doing so can result in replication stall, in cases when a MsgApp is dropped.
+//
+// Returns true if a message was sent, or false otherwise. A message is not sent
+// if the follower log and commit index are up-to-date, the flow is paused (for
+// reasons like in-flight limits), or the message could not be constructed.
+func (r *raft) maybeSendAppend(to uint64, pr *tracker.Progress) bool {
+	if r.disableEagerAppends {
+		return false
+	}
+	return r.maybeSendAppendBuf(to, pr, &r.msgs)
+}
+
+func (r *raft) appendsReady(pr *tracker.Progress) bool {
+	return pr.ShouldSendMsgApp(r.raftLog.lastIndex(), r.raftLog.committed)
+}
+
+// maybeSendAppendBuf implements maybeSendAppend, and puts the messages into the
+// provided buffer.
+func (r *raft) maybeSendAppendBuf(to uint64, pr *tracker.Progress, buf *msgBuf) bool {
+	last, commit := r.raftLog.lastIndex(), r.raftLog.committed
+	if !pr.ShouldSendMsgApp(last, commit) {
 		return false
 	}
 
@@ -610,43 +668,34 @@ func (r *raft) maybeSendAppend(to uint64, sendIfEmpty bool) bool {
 	if err != nil {
 		// The log probably got truncated at >= pr.Next, so we can't catch up the
 		// follower log anymore. Send a snapshot instead.
-		return r.maybeSendSnapshot(to, pr)
+		return r.maybeSendSnapshot(to, pr, buf)
 	}
 
-	var ents []pb.Entry
-	// In a throttled StateReplicate only send empty MsgApp, to ensure progress.
-	// Otherwise, if we had a full Inflights and all inflight messages were in
-	// fact dropped, replication to that follower would stall. Instead, an empty
-	// MsgApp will eventually reach the follower (heartbeats responses prompt the
-	// leader to send an append), allowing it to be acked or rejected, both of
-	// which will clear out Inflights.
-	if pr.State != tracker.StateReplicate || !pr.Inflights.Full() {
-		ents, err = r.raftLog.entries(pr.Next, r.maxMsgSize)
-	}
-	if len(ents) == 0 && !sendIfEmpty {
-		return false
-	}
-	// TODO(pav-kv): move this check up to where err is returned.
-	if err != nil { // send a snapshot if we failed to get the entries
-		return r.maybeSendSnapshot(to, pr)
+	var entries []pb.Entry
+	if pr.CanSendEntries(last) {
+		if entries, err = r.raftLog.entries(pr.Next, r.maxMsgSize); err != nil {
+			// Send a snapshot if we failed to get the entries.
+			return r.maybeSendSnapshot(to, pr, buf)
+		}
 	}
 
-	// Send the actual MsgApp otherwise, and update the progress accordingly.
-	r.send(pb.Message{
+	// Send the MsgApp, and update the progress accordingly.
+	r.sendTo(buf, pb.Message{
 		To:      to,
 		Type:    pb.MsgApp,
 		Index:   prevIndex,
 		LogTerm: prevTerm,
-		Entries: ents,
-		Commit:  r.raftLog.committed,
+		Entries: entries,
+		Commit:  commit,
 	})
-	pr.UpdateOnEntriesSend(len(ents), uint64(payloadsSize(ents)))
+	pr.SentEntries(len(entries), uint64(payloadsSize(entries)))
+	pr.SentCommit(commit)
 	return true
 }
 
 // maybeSendSnapshot fetches a snapshot from Storage, and sends it to the given
 // node. Returns true iff the snapshot message has been emitted successfully.
-func (r *raft) maybeSendSnapshot(to uint64, pr *tracker.Progress) bool {
+func (r *raft) maybeSendSnapshot(to uint64, pr *tracker.Progress, buf *msgBuf) bool {
 	if !pr.RecentActive {
 		r.logger.Debugf("ignore sending snapshot to %x since it is not recently active", to)
 		return false
@@ -669,37 +718,37 @@ func (r *raft) maybeSendSnapshot(to uint64, pr *tracker.Progress) bool {
 	pr.BecomeSnapshot(sindex)
 	r.logger.Debugf("%x paused sending replication messages to %x [%s]", r.id, to, pr)
 
-	r.send(pb.Message{To: to, Type: pb.MsgSnap, Snapshot: &snapshot})
+	r.sendTo(buf, pb.Message{To: to, Type: pb.MsgSnap, Snapshot: &snapshot})
 	return true
 }
 
 // sendHeartbeat sends a heartbeat RPC to the given peer.
 func (r *raft) sendHeartbeat(to uint64, ctx []byte) {
+	pr := r.trk.Progress[to]
 	// Attach the commit as min(to.matched, r.committed).
 	// When the leader sends out heartbeat message,
 	// the receiver(follower) might not be matched with the leader
 	// or it might not have all the committed entries.
 	// The leader MUST NOT forward the follower's commit to
 	// an unmatched index.
-	commit := min(r.trk.Progress[to].Match, r.raftLog.committed)
-	m := pb.Message{
+	commit := min(pr.Match, r.raftLog.committed)
+	r.send(pb.Message{
 		To:      to,
 		Type:    pb.MsgHeartbeat,
 		Commit:  commit,
 		Context: ctx,
-	}
-
-	r.send(m)
+	})
+	pr.SentCommit(commit)
 }
 
 // bcastAppend sends RPC, with entries to all peers that are not up-to-date
 // according to the progress recorded in r.trk.
 func (r *raft) bcastAppend() {
-	r.trk.Visit(func(id uint64, _ *tracker.Progress) {
+	r.trk.Visit(func(id uint64, pr *tracker.Progress) {
 		if id == r.id {
 			return
 		}
-		r.sendAppend(id)
+		r.maybeSendAppend(id, pr)
 	})
 }
 
@@ -1477,10 +1526,9 @@ func stepLeader(r *raft, m pb.Message) error {
 				if pr.State == tracker.StateReplicate {
 					pr.BecomeProbe()
 				}
-				r.sendAppend(m.From)
+				r.maybeSendAppend(m.From, pr)
 			}
 		} else {
-			oldPaused := pr.IsPaused()
 			// We want to update our tracking if the response updates our
 			// matched index or if the response can move a probing peer back
 			// into StateReplicate (see heartbeat_rep_recovers_from_probing.txt
@@ -1517,19 +1565,13 @@ func stepLeader(r *raft, m pb.Message) error {
 					// to respond to pending read index requests
 					releasePendingReadIndexMessages(r)
 					r.bcastAppend()
-				} else if oldPaused {
-					// If we were paused before, this node may be missing the
-					// latest commit index, so send it.
-					r.sendAppend(m.From)
 				}
-				// We've updated flow control information above, which may
-				// allow us to send multiple (size-limited) in-flight messages
-				// at once (such as when transitioning from probe to
-				// replicate, or when freeTo() covers multiple messages). If
-				// we have more entries to send, send as many messages as we
-				// can (without sending empty messages for the commit index)
+				// We've updated flow control information above, which may allow us to
+				// send multiple (size-limited) in-flight messages at once (such as when
+				// transitioning from probe to replicate, or when freeTo() covers
+				// multiple messages). Send as many messages as we can.
 				if r.id != m.From {
-					for r.maybeSendAppend(m.From, false /* sendIfEmpty */) {
+					for r.maybeSendAppend(m.From, pr) {
 					}
 				}
 				// Transfer leadership is in progress.
@@ -1541,24 +1583,8 @@ func stepLeader(r *raft, m pb.Message) error {
 		}
 	case pb.MsgHeartbeatResp:
 		pr.RecentActive = true
-		pr.MsgAppFlowPaused = false
-
-		// NB: if the follower is paused (full Inflights), this will still send an
-		// empty append, allowing it to recover from situations in which all the
-		// messages that filled up Inflights in the first place were dropped. Note
-		// also that the outgoing heartbeat already communicated the commit index.
-		//
-		// If the follower is fully caught up but also in StateProbe (as can happen
-		// if ReportUnreachable was called), we also want to send an append (it will
-		// be empty) to allow the follower to transition back to StateReplicate once
-		// it responds.
-		//
-		// Note that StateSnapshot typically satisfies pr.Match < lastIndex, but
-		// `pr.Paused()` is always true for StateSnapshot, so sendAppend is a
-		// no-op.
-		if pr.Match < r.raftLog.lastIndex() || pr.State == tracker.StateProbe {
-			r.sendAppend(m.From)
-		}
+		pr.PauseMsgAppProbes(false)
+		r.maybeSendAppend(m.From, pr)
 
 		if r.readOnly.option != ReadOnlySafe || len(m.Context) == 0 {
 			return nil
@@ -1591,7 +1617,7 @@ func stepLeader(r *raft, m pb.Message) error {
 		// If snapshot finish, wait for the MsgAppResp from the remote node before sending
 		// out the next MsgApp.
 		// If snapshot failure, wait for a heartbeat interval before next try
-		pr.MsgAppFlowPaused = true
+		pr.PauseMsgAppProbes(true)
 	case pb.MsgUnreachable:
 		// During optimistic replication, if the remote becomes unreachable,
 		// there is huge probability that a MsgApp is lost.
@@ -1628,7 +1654,8 @@ func stepLeader(r *raft, m pb.Message) error {
 			r.sendTimeoutNow(leadTransferee)
 			r.logger.Infof("%x sends MsgTimeoutNow to %x immediately as %x already has up-to-date log", r.id, leadTransferee, leadTransferee)
 		} else {
-			r.sendAppend(leadTransferee)
+			pr.PauseMsgAppProbes(false)
+			r.maybeSendAppend(leadTransferee, pr)
 		}
 	}
 	return nil
@@ -1976,21 +2003,14 @@ func (r *raft) switchToConfig(cfg tracker.Config, trk tracker.ProgressMap) pb.Co
 		return cs
 	}
 
-	if r.maybeCommit() {
-		// If the configuration change means that more entries are committed now,
-		// broadcast/append to everyone in the updated config.
-		r.bcastAppend()
-	} else {
-		// Otherwise, still probe the newly added replicas; there's no reason to
-		// let them wait out a heartbeat interval (or the next incoming
-		// proposal).
-		r.trk.Visit(func(id uint64, pr *tracker.Progress) {
-			if id == r.id {
-				return
-			}
-			r.maybeSendAppend(id, false /* sendIfEmpty */)
-		})
-	}
+	r.maybeCommit()
+	// If the configuration change means that more entries are committed now,
+	// broadcast/append to everyone in the updated config.
+	//
+	// Otherwise, still probe the newly added replicas; there's no reason to let
+	// them wait out a heartbeat interval (or the next incoming proposal).
+	r.bcastAppend()
+
 	// If the leadTransferee was removed or demoted, abort the leadership transfer.
 	if _, tOK := r.trk.Config.Voters.IDs()[r.leadTransferee]; !tOK && r.leadTransferee != 0 {
 		r.abortLeaderTransfer()
diff --git a/raft_snap_test.go b/raft_snap_test.go
index e6058c68..a69d1993 100644
--- a/raft_snap_test.go
+++ b/raft_snap_test.go
@@ -83,8 +83,8 @@ func TestSnapshotFailure(t *testing.T) {
 	if sm.trk.Progress[2].Next != 1 {
 		t.Fatalf("Next = %d, want 1", sm.trk.Progress[2].Next)
 	}
-	if !sm.trk.Progress[2].MsgAppFlowPaused {
-		t.Errorf("MsgAppFlowPaused = %v, want true", sm.trk.Progress[2].MsgAppFlowPaused)
+	if !sm.trk.Progress[2].MsgAppProbesPaused {
+		t.Errorf("msgAppProbesPaused = %v, want true", sm.trk.Progress[2].MsgAppProbesPaused)
 	}
 }
 
@@ -106,8 +106,8 @@ func TestSnapshotSucceed(t *testing.T) {
 	if sm.trk.Progress[2].Next != 12 {
 		t.Fatalf("Next = %d, want 12", sm.trk.Progress[2].Next)
 	}
-	if !sm.trk.Progress[2].MsgAppFlowPaused {
-		t.Errorf("MsgAppFlowPaused = %v, want true", sm.trk.Progress[2].MsgAppFlowPaused)
+	if !sm.trk.Progress[2].MsgAppProbesPaused {
+		t.Errorf("MsgAppProbesPaused = %v, want true", sm.trk.Progress[2].MsgAppProbesPaused)
 	}
 }
 
diff --git a/raft_test.go b/raft_test.go
index 5a258e56..c41c484e 100644
--- a/raft_test.go
+++ b/raft_test.go
@@ -128,21 +128,21 @@ func TestProgressResumeByHeartbeatResp(t *testing.T) {
 	r.becomeCandidate()
 	r.becomeLeader()
 
-	r.trk.Progress[2].MsgAppFlowPaused = true
+	r.trk.Progress[2].PauseMsgAppProbes(true)
 
 	r.Step(pb.Message{From: 1, To: 1, Type: pb.MsgBeat})
-	if !r.trk.Progress[2].MsgAppFlowPaused {
-		t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppFlowPaused)
+	if !r.trk.Progress[2].MsgAppProbesPaused {
+		t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppProbesPaused)
 	}
 
 	r.trk.Progress[2].BecomeReplicate()
-	if r.trk.Progress[2].MsgAppFlowPaused {
-		t.Errorf("paused = %v, want false", r.trk.Progress[2].MsgAppFlowPaused)
+	if r.trk.Progress[2].MsgAppProbesPaused {
+		t.Errorf("paused = %v, want false", r.trk.Progress[2].MsgAppProbesPaused)
 	}
-	r.trk.Progress[2].MsgAppFlowPaused = true
+	r.trk.Progress[2].PauseMsgAppProbes(true)
 	r.Step(pb.Message{From: 2, To: 1, Type: pb.MsgHeartbeatResp})
-	if r.trk.Progress[2].MsgAppFlowPaused {
-		t.Errorf("paused = %v, want false", r.trk.Progress[2].MsgAppFlowPaused)
+	if !r.trk.Progress[2].MsgAppProbesPaused {
+		t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppProbesPaused)
 	}
 }
 
@@ -2764,7 +2764,8 @@ func TestSendAppendForProgressProbe(t *testing.T) {
 	r.becomeCandidate()
 	r.becomeLeader()
 	r.readMessages()
-	r.trk.Progress[2].BecomeProbe()
+	pr2 := r.trk.Progress[2]
+	pr2.BecomeProbe()
 
 	// each round is a heartbeat
 	for i := 0; i < 3; i++ {
@@ -2773,7 +2774,7 @@ func TestSendAppendForProgressProbe(t *testing.T) {
 			// loop. After that, the follower is paused until a heartbeat response is
 			// received.
 			mustAppendEntry(r, pb.Entry{Data: []byte("somedata")})
-			r.sendAppend(2)
+			r.maybeSendAppend(2, pr2)
 			msg := r.readMessages()
 			if len(msg) != 1 {
 				t.Errorf("len(msg) = %d, want %d", len(msg), 1)
@@ -2783,12 +2784,12 @@ func TestSendAppendForProgressProbe(t *testing.T) {
 			}
 		}
 
-		if !r.trk.Progress[2].MsgAppFlowPaused {
-			t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppFlowPaused)
+		if !r.trk.Progress[2].MsgAppProbesPaused {
+			t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppProbesPaused)
 		}
 		for j := 0; j < 10; j++ {
 			mustAppendEntry(r, pb.Entry{Data: []byte("somedata")})
-			r.sendAppend(2)
+			r.maybeSendAppend(2, pr2)
 			if l := len(r.readMessages()); l != 0 {
 				t.Errorf("len(msg) = %d, want %d", l, 0)
 			}
@@ -2798,8 +2799,8 @@ func TestSendAppendForProgressProbe(t *testing.T) {
 		for j := 0; j < r.heartbeatTimeout; j++ {
 			r.Step(pb.Message{From: 1, To: 1, Type: pb.MsgBeat})
 		}
-		if !r.trk.Progress[2].MsgAppFlowPaused {
-			t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppFlowPaused)
+		if !r.trk.Progress[2].MsgAppProbesPaused {
+			t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppProbesPaused)
 		}
 
 		// consume the heartbeat
@@ -2821,8 +2822,8 @@ func TestSendAppendForProgressProbe(t *testing.T) {
 	if msg[0].Index != 0 {
 		t.Errorf("index = %d, want %d", msg[0].Index, 0)
 	}
-	if !r.trk.Progress[2].MsgAppFlowPaused {
-		t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppFlowPaused)
+	if !r.trk.Progress[2].MsgAppProbesPaused {
+		t.Errorf("paused = %v, want true", r.trk.Progress[2].MsgAppProbesPaused)
 	}
 }
 
@@ -2831,11 +2832,12 @@ func TestSendAppendForProgressReplicate(t *testing.T) {
 	r.becomeCandidate()
 	r.becomeLeader()
 	r.readMessages()
-	r.trk.Progress[2].BecomeReplicate()
+	pr2 := r.trk.Progress[2]
+	pr2.BecomeReplicate()
 
 	for i := 0; i < 10; i++ {
 		mustAppendEntry(r, pb.Entry{Data: []byte("somedata")})
-		r.sendAppend(2)
+		r.maybeSendAppend(2, pr2)
 		msgs := r.readMessages()
 		if len(msgs) != 1 {
 			t.Errorf("len(msg) = %d, want %d", len(msgs), 1)
@@ -2848,11 +2850,12 @@ func TestSendAppendForProgressSnapshot(t *testing.T) {
 	r.becomeCandidate()
 	r.becomeLeader()
 	r.readMessages()
-	r.trk.Progress[2].BecomeSnapshot(10)
+	pr2 := r.trk.Progress[2]
+	pr2.BecomeSnapshot(10)
 
 	for i := 0; i < 10; i++ {
 		mustAppendEntry(r, pb.Entry{Data: []byte("somedata")})
-		r.sendAppend(2)
+		r.maybeSendAppend(2, pr2)
 		msgs := r.readMessages()
 		if len(msgs) != 0 {
 			t.Errorf("len(msg) = %d, want %d", len(msgs), 0)
@@ -4671,16 +4674,17 @@ func TestLogReplicationWithReorderedMessage(t *testing.T) {
 	r1.becomeCandidate()
 	r1.becomeLeader()
 	r1.readMessages()
-	r1.trk.Progress[2].BecomeReplicate()
+	pr2 := r1.trk.Progress[2]
+	pr2.BecomeReplicate()
 
 	r2 := newTestRaft(2, 10, 1, newTestMemoryStorage(withPeers(1, 2)))
 
 	// r1 sends 2 MsgApp messages to r2.
 	mustAppendEntry(r1, pb.Entry{Data: []byte("somedata")})
-	r1.sendAppend(2)
+	r1.maybeSendAppend(2, pr2)
 	req1 := expectOneMessage(t, r1)
 	mustAppendEntry(r1, pb.Entry{Data: []byte("somedata")})
-	r1.sendAppend(2)
+	r1.maybeSendAppend(2, pr2)
 	req2 := expectOneMessage(t, r1)
 
 	// r2 receives the second MsgApp first due to reordering.
diff --git a/rafttest/interaction_env_handler_add_nodes.go b/rafttest/interaction_env_handler_add_nodes.go
index e68a295f..5c699eb5 100644
--- a/rafttest/interaction_env_handler_add_nodes.go
+++ b/rafttest/interaction_env_handler_add_nodes.go
@@ -144,6 +144,7 @@ func (env *InteractionEnv) AddNodes(n int, cfg raft.Config, snap pb.Snapshot) er
 		}
 		cfg.Logger = env.Output
 
+		cfg.DisableEagerAppends = true
 		rn, err := raft.NewRawNode(&cfg)
 		if err != nil {
 			return err
diff --git a/rawnode.go b/rawnode.go
index 428ef519..1be65ce1 100644
--- a/rawnode.go
+++ b/rawnode.go
@@ -16,7 +16,6 @@ package raft
 
 import (
 	"errors"
-
 	pb "go.etcd.io/raft/v3/raftpb"
 	"go.etcd.io/raft/v3/tracker"
 )
@@ -136,6 +135,29 @@ func (rn *RawNode) Ready() Ready {
 	return rd
 }
 
+// FlowControl tunes the volume and types of messages that GetMessages call can
+// return to the application.
+type FlowControl struct {
+	// MaxMsgAppBytes limits the number of byte in append messages. Ignored if
+	// zero.
+	MaxMsgAppBytes uint64
+
+	// TODO(pav-kv): specify limits for local storage append messages.
+	// TODO(pav-kv): control the snapshots.
+}
+
+// MessagesTo returns outstanding messages to a particular node. It appends the
+// messages to the given slice, and returns the resulting slice.
+//
+// At the moment, MessagesTo only returns MsgApp or MsgSnap messages, and only
+// if Config.DisableEagerAppends is true. All other messages are communicated
+// via Ready calls.
+//
+// WARNING: this is an experimental API, use it with caution.
+func (rn *RawNode) MessagesTo(id uint64, fc FlowControl, buffer []pb.Message) []pb.Message {
+	return rn.raft.getMessages(id, fc, buffer)
+}
+
 // readyWithoutAccept returns a Ready. This is a read-only operation, i.e. there
 // is no obligation that the Ready must be handled.
 func (rn *RawNode) readyWithoutAccept() Ready {
@@ -185,6 +207,15 @@ func (rn *RawNode) readyWithoutAccept() Ready {
 		}
 	}
 
+	if r.disableEagerAppends && r.state == StateLeader {
+		r.trk.Visit(func(id uint64, pr *tracker.Progress) {
+			if id == r.id {
+				return
+			}
+			rd.Messages = r.getMessages(id, FlowControl{}, rd.Messages)
+		})
+	}
+
 	return rd
 }
 
@@ -463,6 +494,17 @@ func (rn *RawNode) HasReady() bool {
 	if len(r.msgs) > 0 || len(r.msgsAfterAppend) > 0 {
 		return true
 	}
+	if rn.raft.state == StateLeader {
+		ready := false
+		rn.raft.trk.Visit(func(id uint64, pr *tracker.Progress) {
+			if id != rn.raft.id && !ready {
+				ready = rn.raft.appendsReady(pr)
+			}
+		})
+		if ready {
+			return true
+		}
+	}
 	if r.raftLog.hasNextUnstableEnts() || r.raftLog.hasNextCommittedEnts(rn.applyUnstableEntries()) {
 		return true
 	}
diff --git a/testdata/async_storage_writes.txt b/testdata/async_storage_writes.txt
index 02e59e5a..40330fb0 100644
--- a/testdata/async_storage_writes.txt
+++ b/testdata/async_storage_writes.txt
@@ -87,12 +87,12 @@ stabilize
   Entries:
   1/11 EntryNormal ""
   Messages:
-  1->2 MsgApp Term:1 Log:1/10 Commit:10 Entries:[1/11 EntryNormal ""]
-  1->3 MsgApp Term:1 Log:1/10 Commit:10 Entries:[1/11 EntryNormal ""]
   1->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[1/11 EntryNormal ""] Responses:[
     1->1 MsgAppResp Term:1 Log:0/11
     AppendThread->1 MsgStorageAppendResp Term:1 Log:1/11
   ]
+  1->2 MsgApp Term:1 Log:1/10 Commit:10 Entries:[1/11 EntryNormal ""]
+  1->3 MsgApp Term:1 Log:1/10 Commit:10 Entries:[1/11 EntryNormal ""]
 > 2 receiving messages
   1->2 MsgApp Term:1 Log:1/10 Commit:10 Entries:[1/11 EntryNormal ""]
 > 3 receiving messages
@@ -151,12 +151,12 @@ stabilize
   CommittedEntries:
   1/11 EntryNormal ""
   Messages:
-  1->2 MsgApp Term:1 Log:1/11 Commit:11
-  1->3 MsgApp Term:1 Log:1/11 Commit:11
   1->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:11 Vote:1
   1->ApplyThread MsgStorageApply Term:0 Log:0/0 Entries:[1/11 EntryNormal ""] Responses:[
     ApplyThread->1 MsgStorageApplyResp Term:0 Log:0/0 Entries:[1/11 EntryNormal ""]
   ]
+  1->2 MsgApp Term:1 Log:1/11 Commit:11
+  1->3 MsgApp Term:1 Log:1/11 Commit:11
 > 2 receiving messages
   1->2 MsgApp Term:1 Log:1/11 Commit:11
 > 3 receiving messages
@@ -235,12 +235,12 @@ process-ready 1 2 3
   Entries:
   1/12 EntryNormal "prop_1"
   Messages:
-  1->2 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "prop_1"]
-  1->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "prop_1"]
   1->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[1/12 EntryNormal "prop_1"] Responses:[
     1->1 MsgAppResp Term:1 Log:0/12
     AppendThread->1 MsgStorageAppendResp Term:1 Log:1/12
   ]
+  1->2 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "prop_1"]
+  1->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "prop_1"]
 > 2 handling Ready
   <empty Ready>
 > 3 handling Ready
@@ -285,12 +285,12 @@ process-ready 1 2 3
   Entries:
   1/13 EntryNormal "prop_2"
   Messages:
-  1->2 MsgApp Term:1 Log:1/12 Commit:11 Entries:[1/13 EntryNormal "prop_2"]
-  1->3 MsgApp Term:1 Log:1/12 Commit:11 Entries:[1/13 EntryNormal "prop_2"]
   1->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[1/13 EntryNormal "prop_2"] Responses:[
     1->1 MsgAppResp Term:1 Log:0/13
     AppendThread->1 MsgStorageAppendResp Term:1 Log:1/13
   ]
+  1->2 MsgApp Term:1 Log:1/12 Commit:11 Entries:[1/13 EntryNormal "prop_2"]
+  1->3 MsgApp Term:1 Log:1/12 Commit:11 Entries:[1/13 EntryNormal "prop_2"]
 > 2 handling Ready
   <empty Ready>
 > 3 handling Ready
@@ -368,10 +368,6 @@ process-ready 1 2 3
   CommittedEntries:
   1/12 EntryNormal "prop_1"
   Messages:
-  1->2 MsgApp Term:1 Log:1/13 Commit:12
-  1->3 MsgApp Term:1 Log:1/13 Commit:12
-  1->2 MsgApp Term:1 Log:1/13 Commit:12 Entries:[1/14 EntryNormal "prop_3"]
-  1->3 MsgApp Term:1 Log:1/13 Commit:12 Entries:[1/14 EntryNormal "prop_3"]
   1->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:12 Vote:1 Entries:[1/14 EntryNormal "prop_3"] Responses:[
     1->1 MsgAppResp Term:1 Log:0/14
     AppendThread->1 MsgStorageAppendResp Term:1 Log:1/14
@@ -379,6 +375,8 @@ process-ready 1 2 3
   1->ApplyThread MsgStorageApply Term:0 Log:0/0 Entries:[1/12 EntryNormal "prop_1"] Responses:[
     ApplyThread->1 MsgStorageApplyResp Term:0 Log:0/0 Entries:[1/12 EntryNormal "prop_1"]
   ]
+  1->2 MsgApp Term:1 Log:1/13 Commit:12 Entries:[1/14 EntryNormal "prop_3"]
+  1->3 MsgApp Term:1 Log:1/13 Commit:12 Entries:[1/14 EntryNormal "prop_3"]
 > 2 handling Ready
   <empty Ready>
 > 3 handling Ready
@@ -386,9 +384,7 @@ process-ready 1 2 3
 
 deliver-msgs 1 2 3
 ----
-1->2 MsgApp Term:1 Log:1/13 Commit:12
 1->2 MsgApp Term:1 Log:1/13 Commit:12 Entries:[1/14 EntryNormal "prop_3"]
-1->3 MsgApp Term:1 Log:1/13 Commit:12
 1->3 MsgApp Term:1 Log:1/13 Commit:12 Entries:[1/14 EntryNormal "prop_3"]
 
 process-ready 1 2 3
@@ -404,7 +400,6 @@ process-ready 1 2 3
   1/12 EntryNormal "prop_1"
   Messages:
   2->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:12 Vote:1 Entries:[1/14 EntryNormal "prop_3"] Responses:[
-    2->1 MsgAppResp Term:1 Log:0/13
     2->1 MsgAppResp Term:1 Log:0/14
     AppendThread->2 MsgStorageAppendResp Term:1 Log:1/14
   ]
@@ -420,7 +415,6 @@ process-ready 1 2 3
   1/12 EntryNormal "prop_1"
   Messages:
   3->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:12 Vote:1 Entries:[1/14 EntryNormal "prop_3"] Responses:[
-    3->1 MsgAppResp Term:1 Log:0/13
     3->1 MsgAppResp Term:1 Log:0/14
     AppendThread->3 MsgStorageAppendResp Term:1 Log:1/14
   ]
@@ -472,10 +466,6 @@ process-ready 1 2 3
   CommittedEntries:
   1/13 EntryNormal "prop_2"
   Messages:
-  1->2 MsgApp Term:1 Log:1/14 Commit:13
-  1->3 MsgApp Term:1 Log:1/14 Commit:13
-  1->2 MsgApp Term:1 Log:1/14 Commit:13 Entries:[1/15 EntryNormal "prop_4"]
-  1->3 MsgApp Term:1 Log:1/14 Commit:13 Entries:[1/15 EntryNormal "prop_4"]
   1->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:13 Vote:1 Entries:[1/15 EntryNormal "prop_4"] Responses:[
     1->1 MsgAppResp Term:1 Log:0/15
     AppendThread->1 MsgStorageAppendResp Term:1 Log:1/15
@@ -483,6 +473,8 @@ process-ready 1 2 3
   1->ApplyThread MsgStorageApply Term:0 Log:0/0 Entries:[1/13 EntryNormal "prop_2"] Responses:[
     ApplyThread->1 MsgStorageApplyResp Term:0 Log:0/0 Entries:[1/13 EntryNormal "prop_2"]
   ]
+  1->2 MsgApp Term:1 Log:1/14 Commit:13 Entries:[1/15 EntryNormal "prop_4"]
+  1->3 MsgApp Term:1 Log:1/14 Commit:13 Entries:[1/15 EntryNormal "prop_4"]
 > 2 handling Ready
   <empty Ready>
 > 3 handling Ready
@@ -490,9 +482,7 @@ process-ready 1 2 3
 
 deliver-msgs 1 2 3
 ----
-1->2 MsgApp Term:1 Log:1/14 Commit:13
 1->2 MsgApp Term:1 Log:1/14 Commit:13 Entries:[1/15 EntryNormal "prop_4"]
-1->3 MsgApp Term:1 Log:1/14 Commit:13
 1->3 MsgApp Term:1 Log:1/14 Commit:13 Entries:[1/15 EntryNormal "prop_4"]
 
 process-ready 1 2 3
@@ -508,7 +498,6 @@ process-ready 1 2 3
   1/13 EntryNormal "prop_2"
   Messages:
   2->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:13 Vote:1 Entries:[1/15 EntryNormal "prop_4"] Responses:[
-    2->1 MsgAppResp Term:1 Log:0/14
     2->1 MsgAppResp Term:1 Log:0/15
     AppendThread->2 MsgStorageAppendResp Term:1 Log:1/15
   ]
@@ -524,7 +513,6 @@ process-ready 1 2 3
   1/13 EntryNormal "prop_2"
   Messages:
   3->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:13 Vote:1 Entries:[1/15 EntryNormal "prop_4"] Responses:[
-    3->1 MsgAppResp Term:1 Log:0/14
     3->1 MsgAppResp Term:1 Log:0/15
     AppendThread->3 MsgStorageAppendResp Term:1 Log:1/15
   ]
@@ -544,14 +532,12 @@ process-append-thread 1 2 3
   Processing:
   2->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:12 Vote:1 Entries:[1/14 EntryNormal "prop_3"]
   Responses:
-  2->1 MsgAppResp Term:1 Log:0/13
   2->1 MsgAppResp Term:1 Log:0/14
   AppendThread->2 MsgStorageAppendResp Term:1 Log:1/14
 > 3 processing append thread
   Processing:
   3->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:12 Vote:1 Entries:[1/14 EntryNormal "prop_3"]
   Responses:
-  3->1 MsgAppResp Term:1 Log:0/13
   3->1 MsgAppResp Term:1 Log:0/14
   AppendThread->3 MsgStorageAppendResp Term:1 Log:1/14
 
@@ -577,9 +563,7 @@ deliver-msgs 1 2 3
 ----
 1->1 MsgAppResp Term:1 Log:0/14
 AppendThread->1 MsgStorageAppendResp Term:1 Log:1/14
-2->1 MsgAppResp Term:1 Log:0/13
 2->1 MsgAppResp Term:1 Log:0/14
-3->1 MsgAppResp Term:1 Log:0/13
 3->1 MsgAppResp Term:1 Log:0/14
 ApplyThread->1 MsgStorageApplyResp Term:0 Log:0/0 Entries:[1/12 EntryNormal "prop_1"]
 AppendThread->2 MsgStorageAppendResp Term:1 Log:1/14
@@ -595,14 +579,14 @@ process-ready 1 2 3
   CommittedEntries:
   1/14 EntryNormal "prop_3"
   Messages:
-  1->2 MsgApp Term:1 Log:1/15 Commit:14
-  1->3 MsgApp Term:1 Log:1/15 Commit:14
   1->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:14 Vote:1 Responses:[
     AppendThread->1 MsgStorageAppendResp Term:1 Log:1/15
   ]
   1->ApplyThread MsgStorageApply Term:0 Log:0/0 Entries:[1/14 EntryNormal "prop_3"] Responses:[
     ApplyThread->1 MsgStorageApplyResp Term:0 Log:0/0 Entries:[1/14 EntryNormal "prop_3"]
   ]
+  1->2 MsgApp Term:1 Log:1/15 Commit:14
+  1->3 MsgApp Term:1 Log:1/15 Commit:14
 > 2 handling Ready
   <empty Ready>
 > 3 handling Ready
@@ -656,14 +640,12 @@ process-append-thread 1 2 3
   Processing:
   2->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:13 Vote:1 Entries:[1/15 EntryNormal "prop_4"]
   Responses:
-  2->1 MsgAppResp Term:1 Log:0/14
   2->1 MsgAppResp Term:1 Log:0/15
   AppendThread->2 MsgStorageAppendResp Term:1 Log:1/15
 > 3 processing append thread
   Processing:
   3->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:13 Vote:1 Entries:[1/15 EntryNormal "prop_4"]
   Responses:
-  3->1 MsgAppResp Term:1 Log:0/14
   3->1 MsgAppResp Term:1 Log:0/15
   AppendThread->3 MsgStorageAppendResp Term:1 Log:1/15
 
@@ -689,9 +671,7 @@ deliver-msgs 1 2 3
 ----
 1->1 MsgAppResp Term:1 Log:0/15
 AppendThread->1 MsgStorageAppendResp Term:1 Log:1/15
-2->1 MsgAppResp Term:1 Log:0/14
 2->1 MsgAppResp Term:1 Log:0/15
-3->1 MsgAppResp Term:1 Log:0/14
 3->1 MsgAppResp Term:1 Log:0/15
 ApplyThread->1 MsgStorageApplyResp Term:0 Log:0/0 Entries:[1/13 EntryNormal "prop_2"]
 AppendThread->2 MsgStorageAppendResp Term:1 Log:1/15
@@ -707,12 +687,12 @@ process-ready 1 2 3
   CommittedEntries:
   1/15 EntryNormal "prop_4"
   Messages:
-  1->2 MsgApp Term:1 Log:1/15 Commit:15
-  1->3 MsgApp Term:1 Log:1/15 Commit:15
   1->AppendThread MsgStorageAppend Term:1 Log:0/0 Commit:15 Vote:1
   1->ApplyThread MsgStorageApply Term:0 Log:0/0 Entries:[1/15 EntryNormal "prop_4"] Responses:[
     ApplyThread->1 MsgStorageApplyResp Term:0 Log:0/0 Entries:[1/15 EntryNormal "prop_4"]
   ]
+  1->2 MsgApp Term:1 Log:1/15 Commit:15
+  1->3 MsgApp Term:1 Log:1/15 Commit:15
 > 2 handling Ready
   <empty Ready>
 > 3 handling Ready
diff --git a/testdata/async_storage_writes_append_aba_race.txt b/testdata/async_storage_writes_append_aba_race.txt
index 83964fe7..2f5e3cd4 100644
--- a/testdata/async_storage_writes_append_aba_race.txt
+++ b/testdata/async_storage_writes_append_aba_race.txt
@@ -36,16 +36,16 @@ Ready MustSync=true:
 Entries:
 1/12 EntryNormal "init_prop"
 Messages:
+2->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[1/12 EntryNormal "init_prop"] Responses:[
+  2->2 MsgAppResp Term:1 Log:0/12
+  AppendThread->2 MsgStorageAppendResp Term:1 Log:1/12
+]
 2->1 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "init_prop"]
 2->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "init_prop"]
 2->4 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "init_prop"]
 2->5 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "init_prop"]
 2->6 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "init_prop"]
 2->7 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "init_prop"]
-2->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[1/12 EntryNormal "init_prop"] Responses:[
-  2->2 MsgAppResp Term:1 Log:0/12
-  AppendThread->2 MsgStorageAppendResp Term:1 Log:1/12
-]
 
 deliver-msgs 1 drop=(3,4,5,6,7)
 ----
@@ -191,16 +191,16 @@ Lead:3 State:StateLeader
 Entries:
 2/12 EntryNormal ""
 Messages:
+3->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[2/12 EntryNormal ""] Responses:[
+  3->3 MsgAppResp Term:2 Log:0/12
+  AppendThread->3 MsgStorageAppendResp Term:2 Log:2/12
+]
 3->1 MsgApp Term:2 Log:1/11 Commit:11 Entries:[2/12 EntryNormal ""]
 3->2 MsgApp Term:2 Log:1/11 Commit:11 Entries:[2/12 EntryNormal ""]
 3->4 MsgApp Term:2 Log:1/11 Commit:11 Entries:[2/12 EntryNormal ""]
 3->5 MsgApp Term:2 Log:1/11 Commit:11 Entries:[2/12 EntryNormal ""]
 3->6 MsgApp Term:2 Log:1/11 Commit:11 Entries:[2/12 EntryNormal ""]
 3->7 MsgApp Term:2 Log:1/11 Commit:11 Entries:[2/12 EntryNormal ""]
-3->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[2/12 EntryNormal ""] Responses:[
-  3->3 MsgAppResp Term:2 Log:0/12
-  AppendThread->3 MsgStorageAppendResp Term:2 Log:2/12
-]
 
 deliver-msgs 1 drop=(2,4,5,6,7)
 ----
@@ -348,16 +348,16 @@ Lead:4 State:StateLeader
 Entries:
 3/12 EntryNormal ""
 Messages:
+4->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[3/12 EntryNormal ""] Responses:[
+  4->4 MsgAppResp Term:3 Log:0/12
+  AppendThread->4 MsgStorageAppendResp Term:3 Log:3/12
+]
 4->1 MsgApp Term:3 Log:1/11 Commit:11 Entries:[3/12 EntryNormal ""]
 4->2 MsgApp Term:3 Log:1/11 Commit:11 Entries:[3/12 EntryNormal ""]
 4->3 MsgApp Term:3 Log:1/11 Commit:11 Entries:[3/12 EntryNormal ""]
 4->5 MsgApp Term:3 Log:1/11 Commit:11 Entries:[3/12 EntryNormal ""]
 4->6 MsgApp Term:3 Log:1/11 Commit:11 Entries:[3/12 EntryNormal ""]
 4->7 MsgApp Term:3 Log:1/11 Commit:11 Entries:[3/12 EntryNormal ""]
-4->AppendThread MsgStorageAppend Term:0 Log:0/0 Entries:[3/12 EntryNormal ""] Responses:[
-  4->4 MsgAppResp Term:3 Log:0/12
-  AppendThread->4 MsgStorageAppendResp Term:3 Log:3/12
-]
 
 # Step 7: before the new entries reach node 1, it hears of the term change
 # through a heartbeat and persists the new term. Node 1 then receives these
diff --git a/testdata/confchange_disable_validation.txt b/testdata/confchange_disable_validation.txt
index 1a2bc4fd..b0a131b9 100644
--- a/testdata/confchange_disable_validation.txt
+++ b/testdata/confchange_disable_validation.txt
@@ -71,6 +71,6 @@ stabilize
   CommittedEntries:
   1/6 EntryConfChangeV2
   Messages:
-  1->2 MsgApp Term:1 Log:1/5 Commit:5 Entries:[1/6 EntryConfChangeV2]
-  1->3 MsgApp Term:1 Log:1/5 Commit:5 Entries:[1/6 EntryConfChangeV2]
+  1->2 MsgApp Term:1 Log:1/5 Commit:6 Entries:[1/6 EntryConfChangeV2]
+  1->3 MsgApp Term:1 Log:1/5 Commit:6 Entries:[1/6 EntryConfChangeV2]
   INFO 1 switched to configuration voters=(1) learners=(2 3)
diff --git a/testdata/confchange_v1_add_single.txt b/testdata/confchange_v1_add_single.txt
index e54a183f..64a2c2b1 100644
--- a/testdata/confchange_v1_add_single.txt
+++ b/testdata/confchange_v1_add_single.txt
@@ -71,9 +71,9 @@ stabilize
   2->1 MsgAppResp Term:1 Log:0/3 Rejected (Hint: 0)
   DEBUG 1 received MsgAppResp(rejected, hint: (index 0, term 0)) from 2 for index 3
   DEBUG 1 decreased progress of 2 to [StateProbe match=0 next=1]
+> 1 handling Ready
   DEBUG 1 [firstindex: 3, commit: 4] sent snapshot[index: 4, term: 1] to 2 [StateProbe match=0 next=1]
   DEBUG 1 paused sending replication messages to 2 [StateSnapshot match=0 next=1 paused pendingSnap=4]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->2 MsgSnap Term:1 Log:0/0
diff --git a/testdata/confchange_v1_remove_leader.txt b/testdata/confchange_v1_remove_leader.txt
index cc91508a..435b68a1 100644
--- a/testdata/confchange_v1_remove_leader.txt
+++ b/testdata/confchange_v1_remove_leader.txt
@@ -52,25 +52,30 @@ Entries:
 1/4 EntryConfChange r1
 1/5 EntryNormal "foo"
 Messages:
-1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-1->2 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
-1->3 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
+1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+  1/4 EntryConfChange r1
+  1/5 EntryNormal "foo"
+]
+1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+  1/4 EntryConfChange r1
+  1/5 EntryNormal "foo"
+]
 
 # Send response from n2 (which is enough to commit the entries so far next time
 # n1 runs).
 stabilize 2
 ----
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-  1->2 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
+  1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+    1/4 EntryConfChange r1
+    1/5 EntryNormal "foo"
+  ]
 > 2 handling Ready
   Ready MustSync=true:
   Entries:
   1/4 EntryConfChange r1
   1/5 EntryNormal "foo"
   Messages:
-  2->1 MsgAppResp Term:1 Log:0/4
   2->1 MsgAppResp Term:1 Log:0/5
 
 # Put another entry in n1's log.
@@ -92,7 +97,6 @@ stabilize 1
   1->2 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
   1->3 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
 > 1 receiving messages
-  2->1 MsgAppResp Term:1 Log:0/4
   2->1 MsgAppResp Term:1 Log:0/5
 > 1 handling Ready
   Ready MustSync=false:
@@ -101,8 +105,6 @@ stabilize 1
   1/4 EntryConfChange r1
   1/5 EntryNormal "foo"
   Messages:
-  1->2 MsgApp Term:1 Log:1/6 Commit:4
-  1->3 MsgApp Term:1 Log:1/6 Commit:4
   1->2 MsgApp Term:1 Log:1/6 Commit:5
   1->3 MsgApp Term:1 Log:1/6 Commit:5
   INFO 1 switched to configuration voters=(2 3)
@@ -118,7 +120,6 @@ stabilize 2
 ----
 > 2 receiving messages
   1->2 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
-  1->2 MsgApp Term:1 Log:1/6 Commit:4
   1->2 MsgApp Term:1 Log:1/6 Commit:5
 > 2 handling Ready
   Ready MustSync=true:
@@ -131,7 +132,6 @@ stabilize 2
   Messages:
   2->1 MsgAppResp Term:1 Log:0/6
   2->1 MsgAppResp Term:1 Log:0/6
-  2->1 MsgAppResp Term:1 Log:0/6
   INFO 2 switched to configuration voters=(2 3)
 
 # ... which thankfully is what we see on the leader.
@@ -140,16 +140,16 @@ stabilize 1
 > 1 receiving messages
   2->1 MsgAppResp Term:1 Log:0/6
   2->1 MsgAppResp Term:1 Log:0/6
-  2->1 MsgAppResp Term:1 Log:0/6
 
 # When n3 responds, quorum is reached and everything falls into place.
 stabilize
 ----
 > 3 receiving messages
-  1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-  1->3 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
+  1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+    1/4 EntryConfChange r1
+    1/5 EntryNormal "foo"
+  ]
   1->3 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
-  1->3 MsgApp Term:1 Log:1/6 Commit:4
   1->3 MsgApp Term:1 Log:1/6 Commit:5
 > 3 handling Ready
   Ready MustSync=true:
@@ -162,18 +162,14 @@ stabilize
   1/4 EntryConfChange r1
   1/5 EntryNormal "foo"
   Messages:
-  3->1 MsgAppResp Term:1 Log:0/4
   3->1 MsgAppResp Term:1 Log:0/5
   3->1 MsgAppResp Term:1 Log:0/6
   3->1 MsgAppResp Term:1 Log:0/6
-  3->1 MsgAppResp Term:1 Log:0/6
   INFO 3 switched to configuration voters=(2 3)
 > 1 receiving messages
-  3->1 MsgAppResp Term:1 Log:0/4
   3->1 MsgAppResp Term:1 Log:0/5
   3->1 MsgAppResp Term:1 Log:0/6
   3->1 MsgAppResp Term:1 Log:0/6
-  3->1 MsgAppResp Term:1 Log:0/6
 > 1 handling Ready
   Ready MustSync=false:
   HardState Term:1 Vote:1 Commit:6
diff --git a/testdata/confchange_v1_remove_leader_stepdown.txt b/testdata/confchange_v1_remove_leader_stepdown.txt
index fe397650..7c814598 100644
--- a/testdata/confchange_v1_remove_leader_stepdown.txt
+++ b/testdata/confchange_v1_remove_leader_stepdown.txt
@@ -53,25 +53,30 @@ Entries:
 1/4 EntryConfChange r1
 1/5 EntryNormal "foo"
 Messages:
-1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-1->2 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
-1->3 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
+1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+  1/4 EntryConfChange r1
+  1/5 EntryNormal "foo"
+]
+1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+  1/4 EntryConfChange r1
+  1/5 EntryNormal "foo"
+]
 
 # Send response from n2 (which is enough to commit the entries so far next time
 # n1 runs).
 stabilize 2
 ----
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-  1->2 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
+  1->2 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+    1/4 EntryConfChange r1
+    1/5 EntryNormal "foo"
+  ]
 > 2 handling Ready
   Ready MustSync=true:
   Entries:
   1/4 EntryConfChange r1
   1/5 EntryNormal "foo"
   Messages:
-  2->1 MsgAppResp Term:1 Log:0/4
   2->1 MsgAppResp Term:1 Log:0/5
 
 # Put another entry in n1's log.
@@ -91,7 +96,6 @@ stabilize 1
   1->2 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
   1->3 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
 > 1 receiving messages
-  2->1 MsgAppResp Term:1 Log:0/4
   2->1 MsgAppResp Term:1 Log:0/5
 > 1 handling Ready
   Ready MustSync=false:
@@ -100,8 +104,6 @@ stabilize 1
   1/4 EntryConfChange r1
   1/5 EntryNormal "foo"
   Messages:
-  1->2 MsgApp Term:1 Log:1/6 Commit:4
-  1->3 MsgApp Term:1 Log:1/6 Commit:4
   1->2 MsgApp Term:1 Log:1/6 Commit:5
   1->3 MsgApp Term:1 Log:1/6 Commit:5
   INFO 1 switched to configuration voters=(2 3)
@@ -121,7 +123,6 @@ stabilize 2
 ----
 > 2 receiving messages
   1->2 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
-  1->2 MsgApp Term:1 Log:1/6 Commit:4
   1->2 MsgApp Term:1 Log:1/6 Commit:5
 > 2 handling Ready
   Ready MustSync=true:
@@ -134,7 +135,6 @@ stabilize 2
   Messages:
   2->1 MsgAppResp Term:1 Log:0/6
   2->1 MsgAppResp Term:1 Log:0/6
-  2->1 MsgAppResp Term:1 Log:0/6
   INFO 2 switched to configuration voters=(2 3)
 
 # ...because the old leader n1 ignores the append responses.
@@ -143,16 +143,16 @@ stabilize 1
 > 1 receiving messages
   2->1 MsgAppResp Term:1 Log:0/6
   2->1 MsgAppResp Term:1 Log:0/6
-  2->1 MsgAppResp Term:1 Log:0/6
 
 # When n3 responds, quorum is reached and everything falls into place.
 stabilize
 ----
 > 3 receiving messages
-  1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[1/4 EntryConfChange r1]
-  1->3 MsgApp Term:1 Log:1/4 Commit:3 Entries:[1/5 EntryNormal "foo"]
+  1->3 MsgApp Term:1 Log:1/3 Commit:3 Entries:[
+    1/4 EntryConfChange r1
+    1/5 EntryNormal "foo"
+  ]
   1->3 MsgApp Term:1 Log:1/5 Commit:3 Entries:[1/6 EntryNormal "bar"]
-  1->3 MsgApp Term:1 Log:1/6 Commit:4
   1->3 MsgApp Term:1 Log:1/6 Commit:5
 > 3 handling Ready
   Ready MustSync=true:
@@ -165,18 +165,14 @@ stabilize
   1/4 EntryConfChange r1
   1/5 EntryNormal "foo"
   Messages:
-  3->1 MsgAppResp Term:1 Log:0/4
   3->1 MsgAppResp Term:1 Log:0/5
   3->1 MsgAppResp Term:1 Log:0/6
   3->1 MsgAppResp Term:1 Log:0/6
-  3->1 MsgAppResp Term:1 Log:0/6
   INFO 3 switched to configuration voters=(2 3)
 > 1 receiving messages
-  3->1 MsgAppResp Term:1 Log:0/4
   3->1 MsgAppResp Term:1 Log:0/5
   3->1 MsgAppResp Term:1 Log:0/6
   3->1 MsgAppResp Term:1 Log:0/6
-  3->1 MsgAppResp Term:1 Log:0/6
 
 # n1 can no longer propose.
 propose 1 baz
diff --git a/testdata/confchange_v2_add_double_auto.txt b/testdata/confchange_v2_add_double_auto.txt
index bf1dfcbe..81fa8388 100644
--- a/testdata/confchange_v2_add_double_auto.txt
+++ b/testdata/confchange_v2_add_double_auto.txt
@@ -69,8 +69,14 @@ stabilize 1
   Entries:
   1/5 EntryConfChangeV2
   Messages:
-  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[1/4 EntryConfChangeV2 v2 v3]
-  1->3 MsgApp Term:1 Log:1/3 Commit:4 Entries:[1/4 EntryConfChangeV2 v2 v3]
+  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[
+    1/4 EntryConfChangeV2 v2 v3
+    1/5 EntryConfChangeV2
+  ]
+  1->3 MsgApp Term:1 Log:1/3 Commit:4 Entries:[
+    1/4 EntryConfChangeV2 v2 v3
+    1/5 EntryConfChangeV2
+  ]
 
 # First, play out the whole interaction between n1 and n2. We see n1's probe to
 # n2 get rejected (since n2 needs a snapshot); the snapshot is delivered at which
@@ -80,7 +86,10 @@ stabilize 1
 stabilize 1 2
 ----
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[1/4 EntryConfChangeV2 v2 v3]
+  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[
+    1/4 EntryConfChangeV2 v2 v3
+    1/5 EntryConfChangeV2
+  ]
   INFO 2 [term: 0] received a MsgApp message with higher term from 1 [term: 1]
   INFO 2 became follower at term 1
   DEBUG 2 [logterm: 0, index: 3] rejected MsgApp [logterm: 1, index: 3] from 1
@@ -94,9 +103,9 @@ stabilize 1 2
   2->1 MsgAppResp Term:1 Log:0/3 Rejected (Hint: 0)
   DEBUG 1 received MsgAppResp(rejected, hint: (index 0, term 0)) from 2 for index 3
   DEBUG 1 decreased progress of 2 to [StateProbe match=0 next=1]
+> 1 handling Ready
   DEBUG 1 [firstindex: 3, commit: 4] sent snapshot[index: 4, term: 1] to 2 [StateProbe match=0 next=1]
   DEBUG 1 paused sending replication messages to 2 [StateSnapshot match=0 next=1 paused pendingSnap=4]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->2 MsgSnap Term:1 Log:0/0
@@ -156,7 +165,10 @@ stabilize 1 2
 stabilize 1 3
 ----
 > 3 receiving messages
-  1->3 MsgApp Term:1 Log:1/3 Commit:4 Entries:[1/4 EntryConfChangeV2 v2 v3]
+  1->3 MsgApp Term:1 Log:1/3 Commit:4 Entries:[
+    1/4 EntryConfChangeV2 v2 v3
+    1/5 EntryConfChangeV2
+  ]
   INFO 3 [term: 0] received a MsgApp message with higher term from 1 [term: 1]
   INFO 3 became follower at term 1
   DEBUG 3 [logterm: 0, index: 3] rejected MsgApp [logterm: 1, index: 3] from 1
@@ -170,9 +182,9 @@ stabilize 1 3
   3->1 MsgAppResp Term:1 Log:0/3 Rejected (Hint: 0)
   DEBUG 1 received MsgAppResp(rejected, hint: (index 0, term 0)) from 3 for index 3
   DEBUG 1 decreased progress of 3 to [StateProbe match=0 next=1]
+> 1 handling Ready
   DEBUG 1 [firstindex: 3, commit: 5] sent snapshot[index: 5, term: 1] to 3 [StateProbe match=0 next=1]
   DEBUG 1 paused sending replication messages to 3 [StateSnapshot match=0 next=1 paused pendingSnap=5]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->3 MsgSnap Term:1 Log:0/0
@@ -271,10 +283,14 @@ stabilize 1
   1/7 EntryNormal "foo"
   1/8 EntryNormal "bar"
   Messages:
-  1->2 MsgApp Term:1 Log:1/6 Commit:5 Entries:[1/7 EntryNormal "foo"]
-  1->3 MsgApp Term:1 Log:1/6 Commit:5 Entries:[1/7 EntryNormal "foo"]
-  1->2 MsgApp Term:1 Log:1/7 Commit:5 Entries:[1/8 EntryNormal "bar"]
-  1->3 MsgApp Term:1 Log:1/7 Commit:5 Entries:[1/8 EntryNormal "bar"]
+  1->2 MsgApp Term:1 Log:1/6 Commit:5 Entries:[
+    1/7 EntryNormal "foo"
+    1/8 EntryNormal "bar"
+  ]
+  1->3 MsgApp Term:1 Log:1/6 Commit:5 Entries:[
+    1/7 EntryNormal "foo"
+    1/8 EntryNormal "bar"
+  ]
 > 1 receiving messages
   2->1 MsgAppResp Term:1 Log:0/6
   3->1 MsgAppResp Term:1 Log:0/6
@@ -300,13 +316,17 @@ stabilize 1
 stabilize 2 3
 ----
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/6 Commit:5 Entries:[1/7 EntryNormal "foo"]
-  1->2 MsgApp Term:1 Log:1/7 Commit:5 Entries:[1/8 EntryNormal "bar"]
+  1->2 MsgApp Term:1 Log:1/6 Commit:5 Entries:[
+    1/7 EntryNormal "foo"
+    1/8 EntryNormal "bar"
+  ]
   1->2 MsgApp Term:1 Log:1/8 Commit:6
   1->2 MsgApp Term:1 Log:1/8 Commit:6 Entries:[1/9 EntryConfChangeV2]
 > 3 receiving messages
-  1->3 MsgApp Term:1 Log:1/6 Commit:5 Entries:[1/7 EntryNormal "foo"]
-  1->3 MsgApp Term:1 Log:1/7 Commit:5 Entries:[1/8 EntryNormal "bar"]
+  1->3 MsgApp Term:1 Log:1/6 Commit:5 Entries:[
+    1/7 EntryNormal "foo"
+    1/8 EntryNormal "bar"
+  ]
   1->3 MsgApp Term:1 Log:1/8 Commit:6
   1->3 MsgApp Term:1 Log:1/8 Commit:6 Entries:[1/9 EntryConfChangeV2]
 > 2 handling Ready
@@ -319,7 +339,6 @@ stabilize 2 3
   CommittedEntries:
   1/6 EntryConfChangeV2 r2 r3
   Messages:
-  2->1 MsgAppResp Term:1 Log:0/7
   2->1 MsgAppResp Term:1 Log:0/8
   2->1 MsgAppResp Term:1 Log:0/8
   2->1 MsgAppResp Term:1 Log:0/9
@@ -334,7 +353,6 @@ stabilize 2 3
   CommittedEntries:
   1/6 EntryConfChangeV2 r2 r3
   Messages:
-  3->1 MsgAppResp Term:1 Log:0/7
   3->1 MsgAppResp Term:1 Log:0/8
   3->1 MsgAppResp Term:1 Log:0/8
   3->1 MsgAppResp Term:1 Log:0/9
@@ -346,11 +364,9 @@ stabilize 2 3
 stabilize
 ----
 > 1 receiving messages
-  2->1 MsgAppResp Term:1 Log:0/7
   2->1 MsgAppResp Term:1 Log:0/8
   2->1 MsgAppResp Term:1 Log:0/8
   2->1 MsgAppResp Term:1 Log:0/9
-  3->1 MsgAppResp Term:1 Log:0/7
   3->1 MsgAppResp Term:1 Log:0/8
   3->1 MsgAppResp Term:1 Log:0/8
   3->1 MsgAppResp Term:1 Log:0/9
@@ -362,20 +378,12 @@ stabilize
   1/8 EntryNormal "bar"
   1/9 EntryConfChangeV2
   Messages:
-  1->2 MsgApp Term:1 Log:1/9 Commit:7
-  1->3 MsgApp Term:1 Log:1/9 Commit:7
-  1->2 MsgApp Term:1 Log:1/9 Commit:8
-  1->3 MsgApp Term:1 Log:1/9 Commit:8
   1->2 MsgApp Term:1 Log:1/9 Commit:9
   1->3 MsgApp Term:1 Log:1/9 Commit:9
   INFO 1 switched to configuration voters=(1)
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/9 Commit:7
-  1->2 MsgApp Term:1 Log:1/9 Commit:8
   1->2 MsgApp Term:1 Log:1/9 Commit:9
 > 3 receiving messages
-  1->3 MsgApp Term:1 Log:1/9 Commit:7
-  1->3 MsgApp Term:1 Log:1/9 Commit:8
   1->3 MsgApp Term:1 Log:1/9 Commit:9
 > 2 handling Ready
   Ready MustSync=false:
@@ -386,8 +394,6 @@ stabilize
   1/9 EntryConfChangeV2
   Messages:
   2->1 MsgAppResp Term:1 Log:0/9
-  2->1 MsgAppResp Term:1 Log:0/9
-  2->1 MsgAppResp Term:1 Log:0/9
   INFO 2 switched to configuration voters=(1)
 > 3 handling Ready
   Ready MustSync=false:
@@ -398,19 +404,9 @@ stabilize
   1/9 EntryConfChangeV2
   Messages:
   3->1 MsgAppResp Term:1 Log:0/9
-  3->1 MsgAppResp Term:1 Log:0/9
-  3->1 MsgAppResp Term:1 Log:0/9
   INFO 3 switched to configuration voters=(1)
 > 1 receiving messages
   2->1 MsgAppResp Term:1 Log:0/9
   raft: cannot step as peer not found
-  2->1 MsgAppResp Term:1 Log:0/9
-  raft: cannot step as peer not found
-  2->1 MsgAppResp Term:1 Log:0/9
-  raft: cannot step as peer not found
-  3->1 MsgAppResp Term:1 Log:0/9
-  raft: cannot step as peer not found
-  3->1 MsgAppResp Term:1 Log:0/9
-  raft: cannot step as peer not found
   3->1 MsgAppResp Term:1 Log:0/9
   raft: cannot step as peer not found
diff --git a/testdata/confchange_v2_add_double_implicit.txt b/testdata/confchange_v2_add_double_implicit.txt
index 536d66b8..e523bc41 100644
--- a/testdata/confchange_v2_add_double_implicit.txt
+++ b/testdata/confchange_v2_add_double_implicit.txt
@@ -61,9 +61,15 @@ stabilize 1 2
   Entries:
   1/5 EntryConfChangeV2
   Messages:
-  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[1/4 EntryConfChangeV2 v2]
+  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[
+    1/4 EntryConfChangeV2 v2
+    1/5 EntryConfChangeV2
+  ]
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[1/4 EntryConfChangeV2 v2]
+  1->2 MsgApp Term:1 Log:1/3 Commit:4 Entries:[
+    1/4 EntryConfChangeV2 v2
+    1/5 EntryConfChangeV2
+  ]
   INFO 2 [term: 0] received a MsgApp message with higher term from 1 [term: 1]
   INFO 2 became follower at term 1
   DEBUG 2 [logterm: 0, index: 3] rejected MsgApp [logterm: 1, index: 3] from 1
@@ -77,9 +83,9 @@ stabilize 1 2
   2->1 MsgAppResp Term:1 Log:0/3 Rejected (Hint: 0)
   DEBUG 1 received MsgAppResp(rejected, hint: (index 0, term 0)) from 2 for index 3
   DEBUG 1 decreased progress of 2 to [StateProbe match=0 next=1]
+> 1 handling Ready
   DEBUG 1 [firstindex: 3, commit: 4] sent snapshot[index: 4, term: 1] to 2 [StateProbe match=0 next=1]
   DEBUG 1 paused sending replication messages to 2 [StateSnapshot match=0 next=1 paused pendingSnap=4]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->2 MsgSnap Term:1 Log:0/0
diff --git a/testdata/confchange_v2_add_single_auto.txt b/testdata/confchange_v2_add_single_auto.txt
index 1c487da8..09a674e7 100644
--- a/testdata/confchange_v2_add_single_auto.txt
+++ b/testdata/confchange_v2_add_single_auto.txt
@@ -72,9 +72,9 @@ stabilize
   2->1 MsgAppResp Term:1 Log:0/3 Rejected (Hint: 0)
   DEBUG 1 received MsgAppResp(rejected, hint: (index 0, term 0)) from 2 for index 3
   DEBUG 1 decreased progress of 2 to [StateProbe match=0 next=1]
+> 1 handling Ready
   DEBUG 1 [firstindex: 3, commit: 4] sent snapshot[index: 4, term: 1] to 2 [StateProbe match=0 next=1]
   DEBUG 1 paused sending replication messages to 2 [StateSnapshot match=0 next=1 paused pendingSnap=4]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->2 MsgSnap Term:1 Log:0/0
diff --git a/testdata/confchange_v2_add_single_explicit.txt b/testdata/confchange_v2_add_single_explicit.txt
index 123cd17a..65334f92 100644
--- a/testdata/confchange_v2_add_single_explicit.txt
+++ b/testdata/confchange_v2_add_single_explicit.txt
@@ -72,9 +72,9 @@ stabilize 1 2
   2->1 MsgAppResp Term:1 Log:0/3 Rejected (Hint: 0)
   DEBUG 1 received MsgAppResp(rejected, hint: (index 0, term 0)) from 2 for index 3
   DEBUG 1 decreased progress of 2 to [StateProbe match=0 next=1]
+> 1 handling Ready
   DEBUG 1 [firstindex: 3, commit: 4] sent snapshot[index: 4, term: 1] to 2 [StateProbe match=0 next=1]
   DEBUG 1 paused sending replication messages to 2 [StateSnapshot match=0 next=1 paused pendingSnap=4]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->2 MsgSnap Term:1 Log:0/0
@@ -130,21 +130,23 @@ stabilize
   1/5 EntryNormal ""
   1/6 EntryConfChangeV2
   Messages:
-  1->2 MsgApp Term:1 Log:1/4 Commit:4 Entries:[1/5 EntryNormal ""]
-  1->2 MsgApp Term:1 Log:1/5 Commit:4 Entries:[1/6 EntryConfChangeV2]
+  1->2 MsgApp Term:1 Log:1/4 Commit:4 Entries:[
+    1/5 EntryNormal ""
+    1/6 EntryConfChangeV2
+  ]
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/4 Commit:4 Entries:[1/5 EntryNormal ""]
-  1->2 MsgApp Term:1 Log:1/5 Commit:4 Entries:[1/6 EntryConfChangeV2]
+  1->2 MsgApp Term:1 Log:1/4 Commit:4 Entries:[
+    1/5 EntryNormal ""
+    1/6 EntryConfChangeV2
+  ]
 > 2 handling Ready
   Ready MustSync=true:
   Entries:
   1/5 EntryNormal ""
   1/6 EntryConfChangeV2
   Messages:
-  2->1 MsgAppResp Term:1 Log:0/5
   2->1 MsgAppResp Term:1 Log:0/6
 > 1 receiving messages
-  2->1 MsgAppResp Term:1 Log:0/5
   2->1 MsgAppResp Term:1 Log:0/6
 > 1 handling Ready
   Ready MustSync=false:
@@ -153,11 +155,9 @@ stabilize
   1/5 EntryNormal ""
   1/6 EntryConfChangeV2
   Messages:
-  1->2 MsgApp Term:1 Log:1/6 Commit:5
   1->2 MsgApp Term:1 Log:1/6 Commit:6
   INFO 1 switched to configuration voters=(1 2)
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/6 Commit:5
   1->2 MsgApp Term:1 Log:1/6 Commit:6
 > 2 handling Ready
   Ready MustSync=false:
@@ -167,11 +167,9 @@ stabilize
   1/6 EntryConfChangeV2
   Messages:
   2->1 MsgAppResp Term:1 Log:0/6
-  2->1 MsgAppResp Term:1 Log:0/6
   INFO 2 switched to configuration voters=(1 2)
 > 1 receiving messages
   2->1 MsgAppResp Term:1 Log:0/6
-  2->1 MsgAppResp Term:1 Log:0/6
 
 # Check that trying to transition out again won't do anything.
 propose-conf-change 1
diff --git a/testdata/confchange_v2_replace_leader.txt b/testdata/confchange_v2_replace_leader.txt
index ae43ce21..c31adad1 100644
--- a/testdata/confchange_v2_replace_leader.txt
+++ b/testdata/confchange_v2_replace_leader.txt
@@ -284,12 +284,10 @@ stabilize
   CommittedEntries:
   2/5 EntryNormal ""
   Messages:
-  4->1 MsgApp Term:2 Log:2/5 Commit:4
   4->1 MsgApp Term:2 Log:2/5 Commit:5
   4->2 MsgApp Term:2 Log:2/5 Commit:5
   4->3 MsgApp Term:2 Log:2/5 Commit:5
 > 1 receiving messages
-  4->1 MsgApp Term:2 Log:2/5 Commit:4
   4->1 MsgApp Term:2 Log:2/5 Commit:5
 > 2 receiving messages
   4->2 MsgApp Term:2 Log:2/5 Commit:5
@@ -302,7 +300,6 @@ stabilize
   2/5 EntryNormal ""
   Messages:
   1->4 MsgAppResp Term:2 Log:0/5
-  1->4 MsgAppResp Term:2 Log:0/5
 > 2 handling Ready
   Ready MustSync=false:
   HardState Term:2 Vote:4 Commit:5
@@ -318,7 +315,6 @@ stabilize
   Messages:
   3->4 MsgAppResp Term:2 Log:0/5
 > 4 receiving messages
-  1->4 MsgAppResp Term:2 Log:0/5
   1->4 MsgAppResp Term:2 Log:0/5
   2->4 MsgAppResp Term:2 Log:0/5
   3->4 MsgAppResp Term:2 Log:0/5
diff --git a/testdata/heartbeat_resp_recovers_from_probing.txt b/testdata/heartbeat_resp_recovers_from_probing.txt
index e606a155..76d75a26 100644
--- a/testdata/heartbeat_resp_recovers_from_probing.txt
+++ b/testdata/heartbeat_resp_recovers_from_probing.txt
@@ -55,33 +55,25 @@ stabilize
   Messages:
   1->2 MsgHeartbeat Term:1 Log:0/0 Commit:11
   1->3 MsgHeartbeat Term:1 Log:0/0 Commit:11
+  1->2 MsgApp Term:1 Log:1/11 Commit:11
 > 2 receiving messages
   1->2 MsgHeartbeat Term:1 Log:0/0 Commit:11
+  1->2 MsgApp Term:1 Log:1/11 Commit:11
 > 3 receiving messages
   1->3 MsgHeartbeat Term:1 Log:0/0 Commit:11
 > 2 handling Ready
   Ready MustSync=false:
   Messages:
   2->1 MsgHeartbeatResp Term:1 Log:0/0
+  2->1 MsgAppResp Term:1 Log:0/11
 > 3 handling Ready
   Ready MustSync=false:
   Messages:
   3->1 MsgHeartbeatResp Term:1 Log:0/0
 > 1 receiving messages
   2->1 MsgHeartbeatResp Term:1 Log:0/0
-  3->1 MsgHeartbeatResp Term:1 Log:0/0
-> 1 handling Ready
-  Ready MustSync=false:
-  Messages:
-  1->2 MsgApp Term:1 Log:1/11 Commit:11
-> 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/11 Commit:11
-> 2 handling Ready
-  Ready MustSync=false:
-  Messages:
-  2->1 MsgAppResp Term:1 Log:0/11
-> 1 receiving messages
   2->1 MsgAppResp Term:1 Log:0/11
+  3->1 MsgHeartbeatResp Term:1 Log:0/0
 
 status 1
 ----
diff --git a/testdata/lagging_commit.txt b/testdata/lagging_commit.txt
index 8f8ba336..fe1bf413 100644
--- a/testdata/lagging_commit.txt
+++ b/testdata/lagging_commit.txt
@@ -39,10 +39,14 @@ ok
 
 deliver-msgs 2 3
 ----
-1->2 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "data1"]
-1->2 MsgApp Term:1 Log:1/12 Commit:11 Entries:[1/13 EntryNormal "data2"]
-1->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "data1"]
-1->3 MsgApp Term:1 Log:1/12 Commit:11 Entries:[1/13 EntryNormal "data2"]
+1->2 MsgApp Term:1 Log:1/11 Commit:11 Entries:[
+  1/12 EntryNormal "data1"
+  1/13 EntryNormal "data2"
+]
+1->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[
+  1/12 EntryNormal "data1"
+  1/13 EntryNormal "data2"
+]
 
 process-ready 3
 ----
@@ -51,14 +55,12 @@ Entries:
 1/12 EntryNormal "data1"
 1/13 EntryNormal "data2"
 Messages:
-3->1 MsgAppResp Term:1 Log:0/12
 3->1 MsgAppResp Term:1 Log:0/13
 
 # Suppose there is a network blip which prevents the leader learning that the
 # follower 3 has appended the proposed entries to the log.
 deliver-msgs drop=(1)
 ----
-dropped: 3->1 MsgAppResp Term:1 Log:0/12
 dropped: 3->1 MsgAppResp Term:1 Log:0/13
 
 # In the meantime, the entries are committed, and the leader sends the commit
@@ -71,10 +73,8 @@ stabilize 1 2
   1/12 EntryNormal "data1"
   1/13 EntryNormal "data2"
   Messages:
-  2->1 MsgAppResp Term:1 Log:0/12
   2->1 MsgAppResp Term:1 Log:0/13
 > 1 receiving messages
-  2->1 MsgAppResp Term:1 Log:0/12
   2->1 MsgAppResp Term:1 Log:0/13
 > 1 handling Ready
   Ready MustSync=false:
@@ -83,12 +83,9 @@ stabilize 1 2
   1/12 EntryNormal "data1"
   1/13 EntryNormal "data2"
   Messages:
-  1->2 MsgApp Term:1 Log:1/13 Commit:12
-  1->3 MsgApp Term:1 Log:1/13 Commit:12
   1->2 MsgApp Term:1 Log:1/13 Commit:13
   1->3 MsgApp Term:1 Log:1/13 Commit:13
 > 2 receiving messages
-  1->2 MsgApp Term:1 Log:1/13 Commit:12
   1->2 MsgApp Term:1 Log:1/13 Commit:13
 > 2 handling Ready
   Ready MustSync=false:
@@ -98,16 +95,13 @@ stabilize 1 2
   1/13 EntryNormal "data2"
   Messages:
   2->1 MsgAppResp Term:1 Log:0/13
-  2->1 MsgAppResp Term:1 Log:0/13
 > 1 receiving messages
   2->1 MsgAppResp Term:1 Log:0/13
-  2->1 MsgAppResp Term:1 Log:0/13
 
 # The network blip prevents the follower 3 from learning that the previously
 # appended entries are now committed.
 deliver-msgs drop=(3)
 ----
-dropped: 1->3 MsgApp Term:1 Log:1/13 Commit:12
 dropped: 1->3 MsgApp Term:1 Log:1/13 Commit:13
 
 # The network blip ends here.
@@ -116,7 +110,7 @@ status 1
 ----
 1: StateReplicate match=13 next=14
 2: StateReplicate match=13 next=14
-3: StateReplicate match=11 next=14 inflight=2
+3: StateReplicate match=11 next=14 inflight=1
 
 # The leader still observes that the entries are in-flight to the follower 3,
 # since it hasn't heard from it. Nothing triggers updating the follower's
diff --git a/testdata/prevote.txt b/testdata/prevote.txt
index db763d35..a7a3fecf 100644
--- a/testdata/prevote.txt
+++ b/testdata/prevote.txt
@@ -90,9 +90,9 @@ stabilize
   CommittedEntries:
   1/12 EntryNormal "prop_1"
   Messages:
+  1->3 MsgPreVoteResp Term:1 Log:0/0 Rejected (Hint: 0)
   1->2 MsgApp Term:1 Log:1/12 Commit:12
   1->3 MsgApp Term:1 Log:1/12 Commit:12
-  1->3 MsgPreVoteResp Term:1 Log:0/0 Rejected (Hint: 0)
 > 2 handling Ready
   Ready MustSync=false:
   Messages:
@@ -102,8 +102,8 @@ stabilize
 > 3 receiving messages
   1->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "prop_1"]
   INFO 3 became follower at term 1
-  1->3 MsgApp Term:1 Log:1/12 Commit:12
   1->3 MsgPreVoteResp Term:1 Log:0/0 Rejected (Hint: 0)
+  1->3 MsgApp Term:1 Log:1/12 Commit:12
   2->3 MsgPreVoteResp Term:1 Log:0/0 Rejected (Hint: 0)
 > 2 handling Ready
   Ready MustSync=false:
diff --git a/testdata/probe_and_replicate.txt b/testdata/probe_and_replicate.txt
index c4100e97..832be27b 100644
--- a/testdata/probe_and_replicate.txt
+++ b/testdata/probe_and_replicate.txt
@@ -513,18 +513,6 @@ stabilize 1 2
   2->1 MsgAppResp Term:8 Log:0/21
 > 1 receiving messages
   2->1 MsgAppResp Term:8 Log:0/21
-> 1 handling Ready
-  Ready MustSync=false:
-  Messages:
-  1->2 MsgApp Term:8 Log:8/21 Commit:18
-> 2 receiving messages
-  1->2 MsgApp Term:8 Log:8/21 Commit:18
-> 2 handling Ready
-  Ready MustSync=false:
-  Messages:
-  2->1 MsgAppResp Term:8 Log:0/21
-> 1 receiving messages
-  2->1 MsgAppResp Term:8 Log:0/21
 
 stabilize 1 3
 ----
diff --git a/testdata/replicate_pause.txt b/testdata/replicate_pause.txt
index d9cee59f..326f5c23 100644
--- a/testdata/replicate_pause.txt
+++ b/testdata/replicate_pause.txt
@@ -47,8 +47,8 @@ ok
 status 1
 ----
 1: StateReplicate match=14 next=15
-2: StateReplicate match=11 next=15 paused inflight=3[full]
-3: StateReplicate match=11 next=15 paused inflight=3[full]
+2: StateReplicate match=11 next=15 inflight=1
+3: StateReplicate match=11 next=15 inflight=1
 
 log-level none
 ----
@@ -68,14 +68,17 @@ status 1
 ----
 1: StateReplicate match=14 next=15
 2: StateReplicate match=14 next=15
-3: StateReplicate match=11 next=15 paused inflight=3[full]
+3: StateReplicate match=11 next=15 inflight=1
 
 # Drop append messages to node 3.
 deliver-msgs drop=3
 ----
-dropped: 1->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[1/12 EntryNormal "prop_1_12"]
-dropped: 1->3 MsgApp Term:1 Log:1/12 Commit:11 Entries:[1/13 EntryNormal "prop_1_13"]
-dropped: 1->3 MsgApp Term:1 Log:1/13 Commit:11 Entries:[1/14 EntryNormal "prop_1_14"]
+dropped: 1->3 MsgApp Term:1 Log:1/11 Commit:11 Entries:[
+  1/12 EntryNormal "prop_1_12"
+  1/13 EntryNormal "prop_1_13"
+  1/14 EntryNormal "prop_1_14"
+]
+dropped: 1->3 MsgApp Term:1 Log:1/14 Commit:14
 
 
 # Repeat committing 3 entries.
@@ -95,8 +98,8 @@ ok
 status 1
 ----
 1: StateReplicate match=14 next=15
-2: StateReplicate match=14 next=18 paused inflight=3[full]
-3: StateReplicate match=11 next=15 paused inflight=3[full]
+2: StateReplicate match=14 next=15
+3: StateReplicate match=11 next=15 inflight=1
 
 log-level none
 ----
@@ -116,7 +119,7 @@ status 1
 ----
 1: StateReplicate match=17 next=18
 2: StateReplicate match=17 next=18
-3: StateReplicate match=11 next=15 paused inflight=3[full]
+3: StateReplicate match=11 next=18 inflight=2
 
 # Make a heartbeat roundtrip.
 tick-heartbeat 1
@@ -136,6 +139,14 @@ stabilize 2 3
 > 2 receiving messages
   1->2 MsgHeartbeat Term:1 Log:0/0 Commit:17
 > 3 receiving messages
+  1->3 MsgApp Term:1 Log:1/14 Commit:14 Entries:[
+    1/15 EntryNormal "prop_1_15"
+    1/16 EntryNormal "prop_1_16"
+    1/17 EntryNormal "prop_1_17"
+  ]
+  DEBUG 3 [logterm: 0, index: 14] rejected MsgApp [logterm: 1, index: 14] from 1
+  1->3 MsgApp Term:1 Log:1/17 Commit:17
+  DEBUG 3 [logterm: 0, index: 17] rejected MsgApp [logterm: 1, index: 17] from 1
   1->3 MsgHeartbeat Term:1 Log:0/0 Commit:11
 > 2 handling Ready
   Ready MustSync=false:
@@ -145,6 +156,8 @@ stabilize 2 3
   Ready MustSync=false:
   Messages:
   3->1 MsgHeartbeatResp Term:1 Log:0/0
+  3->1 MsgAppResp Term:1 Log:1/14 Rejected (Hint: 11)
+  3->1 MsgAppResp Term:1 Log:1/17 Rejected (Hint: 11)
 
 # After handling heartbeat responses, node 1 sends an empty MsgApp to a
 # throttled node 3 because it hasn't yet replied to a single MsgApp, and the
@@ -154,21 +167,54 @@ stabilize 1
 > 1 receiving messages
   2->1 MsgHeartbeatResp Term:1 Log:0/0
   3->1 MsgHeartbeatResp Term:1 Log:0/0
+  3->1 MsgAppResp Term:1 Log:1/14 Rejected (Hint: 11)
+  DEBUG 1 received MsgAppResp(rejected, hint: (index 11, term 1)) from 3 for index 14
+  DEBUG 1 decreased progress of 3 to [StateReplicate match=11 next=12 inflight=2]
+  3->1 MsgAppResp Term:1 Log:1/17 Rejected (Hint: 11)
+  DEBUG 1 received MsgAppResp(rejected, hint: (index 11, term 1)) from 3 for index 17
 > 1 handling Ready
   Ready MustSync=false:
   Messages:
-  1->3 MsgApp Term:1 Log:1/14 Commit:17
+  1->3 MsgApp Term:1 Log:1/11 Commit:17 Entries:[
+    1/12 EntryNormal "prop_1_12"
+    1/13 EntryNormal "prop_1_13"
+    1/14 EntryNormal "prop_1_14"
+    1/15 EntryNormal "prop_1_15"
+    1/16 EntryNormal "prop_1_16"
+    1/17 EntryNormal "prop_1_17"
+  ]
 
 # Node 3 finally receives a MsgApp, but there was a gap, so it rejects it.
 stabilize 3
 ----
 > 3 receiving messages
-  1->3 MsgApp Term:1 Log:1/14 Commit:17
-  DEBUG 3 [logterm: 0, index: 14] rejected MsgApp [logterm: 1, index: 14] from 1
+  1->3 MsgApp Term:1 Log:1/11 Commit:17 Entries:[
+    1/12 EntryNormal "prop_1_12"
+    1/13 EntryNormal "prop_1_13"
+    1/14 EntryNormal "prop_1_14"
+    1/15 EntryNormal "prop_1_15"
+    1/16 EntryNormal "prop_1_16"
+    1/17 EntryNormal "prop_1_17"
+  ]
 > 3 handling Ready
-  Ready MustSync=false:
+  Ready MustSync=true:
+  HardState Term:1 Vote:1 Commit:17
+  Entries:
+  1/12 EntryNormal "prop_1_12"
+  1/13 EntryNormal "prop_1_13"
+  1/14 EntryNormal "prop_1_14"
+  1/15 EntryNormal "prop_1_15"
+  1/16 EntryNormal "prop_1_16"
+  1/17 EntryNormal "prop_1_17"
+  CommittedEntries:
+  1/12 EntryNormal "prop_1_12"
+  1/13 EntryNormal "prop_1_13"
+  1/14 EntryNormal "prop_1_14"
+  1/15 EntryNormal "prop_1_15"
+  1/16 EntryNormal "prop_1_16"
+  1/17 EntryNormal "prop_1_17"
   Messages:
-  3->1 MsgAppResp Term:1 Log:1/14 Rejected (Hint: 11)
+  3->1 MsgAppResp Term:1 Log:0/17
 
 log-level none
 ----
diff --git a/testdata/slow_follower_after_compaction.txt b/testdata/slow_follower_after_compaction.txt
index 0d3d48c8..a033952d 100644
--- a/testdata/slow_follower_after_compaction.txt
+++ b/testdata/slow_follower_after_compaction.txt
@@ -81,13 +81,18 @@ status 1
 ----
 1: StateReplicate match=18 next=19
 2: StateReplicate match=18 next=19
-3: StateReplicate match=14 next=17 paused inflight=2[full]
+3: StateReplicate match=14 next=19 inflight=1
 
 # Break the MsgApp flow from the leader to node 3.
 deliver-msgs drop=3
 ----
-dropped: 1->3 MsgApp Term:1 Log:1/14 Commit:14 Entries:[1/15 EntryNormal "prop_1_15"]
-dropped: 1->3 MsgApp Term:1 Log:1/15 Commit:14 Entries:[1/16 EntryNormal "prop_1_16"]
+dropped: 1->3 MsgApp Term:1 Log:1/14 Commit:14 Entries:[
+  1/15 EntryNormal "prop_1_15"
+  1/16 EntryNormal "prop_1_16"
+  1/17 EntryNormal "prop_1_17"
+  1/18 EntryNormal "prop_1_18"
+]
+dropped: 1->3 MsgApp Term:1 Log:1/18 Commit:18
 
 # Truncate the leader's log beyond node 3 log size.
 compact 1 17
diff --git a/testdata/snapshot_succeed_via_app_resp.txt b/testdata/snapshot_succeed_via_app_resp.txt
index 5c4b0c61..ee4c8706 100644
--- a/testdata/snapshot_succeed_via_app_resp.txt
+++ b/testdata/snapshot_succeed_via_app_resp.txt
@@ -86,9 +86,9 @@ stabilize 1
 ----
 > 1 receiving messages
   3->1 MsgHeartbeatResp Term:1 Log:0/0
+> 1 handling Ready
   DEBUG 1 [firstindex: 12, commit: 11] sent snapshot[index: 11, term: 1] to 3 [StateProbe match=0 next=11]
   DEBUG 1 paused sending replication messages to 3 [StateSnapshot match=0 next=11 paused pendingSnap=11]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->3 MsgSnap Term:1 Log:0/0
diff --git a/testdata/snapshot_succeed_via_app_resp_behind.txt b/testdata/snapshot_succeed_via_app_resp_behind.txt
index b0f5883b..beec45f3 100644
--- a/testdata/snapshot_succeed_via_app_resp_behind.txt
+++ b/testdata/snapshot_succeed_via_app_resp_behind.txt
@@ -123,9 +123,9 @@ stabilize 1
   3->1 MsgAppResp Term:1 Log:1/10 Rejected (Hint: 5)
   DEBUG 1 received MsgAppResp(rejected, hint: (index 5, term 1)) from 3 for index 10
   DEBUG 1 decreased progress of 3 to [StateProbe match=0 next=6]
+> 1 handling Ready
   DEBUG 1 [firstindex: 11, commit: 12] sent snapshot[index: 12, term: 1] to 3 [StateProbe match=0 next=6]
   DEBUG 1 paused sending replication messages to 3 [StateSnapshot match=0 next=6 paused pendingSnap=12]
-> 1 handling Ready
   Ready MustSync=false:
   Messages:
   1->3 MsgSnap Term:1 Log:0/0
diff --git a/tracker/inflights.go b/tracker/inflights.go
index cb091e54..e22bcb8d 100644
--- a/tracker/inflights.go
+++ b/tracker/inflights.go
@@ -32,6 +32,8 @@ type Inflights struct {
 	count int    // number of inflight messages in the buffer
 	bytes uint64 // number of inflight bytes
 
+	// TODO(pav-kv): do not store the limits here, pass them to methods. For flow
+	// control, we need to support dynamic limits.
 	size     int    // the max number of inflight messages
 	maxBytes uint64 // the max total byte size of inflight messages
 
diff --git a/tracker/progress.go b/tracker/progress.go
index cb4312a9..53157783 100644
--- a/tracker/progress.go
+++ b/tracker/progress.go
@@ -27,6 +27,9 @@ import (
 // NB(tbg): Progress is basically a state machine whose transitions are mostly
 // strewn around `*raft.raft`. Additionally, some fields are only used when in a
 // certain State. All of this isn't ideal.
+//
+// TODO(pav-kv): consolidate all flow control state changes here. Much of the
+// transitions in raft.go logically belong here.
 type Progress struct {
 	// Match is the index up to which the follower's log is known to match the
 	// leader's.
@@ -37,6 +40,11 @@ type Progress struct {
 	// Invariant: 0 <= Match < Next.
 	Next uint64
 
+	// pendingCommit is the highest commit index in flight to the follower.
+	//
+	// Invariant: 0 <= pendingCommit < Next.
+	pendingCommit uint64
+
 	// State defines how the leader should interact with the follower.
 	//
 	// When in StateProbe, leader sends at most one replication message
@@ -79,13 +87,13 @@ type Progress struct {
 	// This is always true on the leader.
 	RecentActive bool
 
-	// MsgAppFlowPaused is used when the MsgApp flow to a node is throttled. This
-	// happens in StateProbe, or StateReplicate with saturated Inflights. In both
-	// cases, we need to continue sending MsgApp once in a while to guarantee
-	// progress, but we only do so when MsgAppFlowPaused is false (it is reset on
-	// receiving a heartbeat response), to not overflow the receiver. See
-	// IsPaused().
-	MsgAppFlowPaused bool
+	// MsgAppProbesPaused set to true prevents sending "probe" MsgApp messages to
+	// this follower. Used in StateProbe, or StateReplicate when all entries are
+	// in-flight or the in-flight volume exceeds limits. See ShouldSendMsgApp().
+	//
+	// TODO(pav-kv): unexport this field. It is used by a few tests, but should be
+	// replaced by PauseMsgAppProbes() and ShouldSendMsgApp().
+	MsgAppProbesPaused bool
 
 	// Inflights is a sliding window for the inflight messages.
 	// Each inflight message contains one or more log entries.
@@ -105,10 +113,10 @@ type Progress struct {
 	IsLearner bool
 }
 
-// ResetState moves the Progress into the specified State, resetting MsgAppFlowPaused,
+// ResetState moves the Progress into the specified State, resetting MsgAppProbesPaused,
 // PendingSnapshot, and Inflights.
 func (pr *Progress) ResetState(state StateType) {
-	pr.MsgAppFlowPaused = false
+	pr.PauseMsgAppProbes(false)
 	pr.PendingSnapshot = 0
 	pr.State = state
 	pr.Inflights.reset()
@@ -127,6 +135,7 @@ func (pr *Progress) BecomeProbe() {
 	} else {
 		pr.ResetState(StateProbe)
 		pr.Next = pr.Match + 1
+		pr.pendingCommit = min(pr.pendingCommit, pr.Match)
 	}
 }
 
@@ -134,6 +143,7 @@ func (pr *Progress) BecomeProbe() {
 func (pr *Progress) BecomeReplicate() {
 	pr.ResetState(StateReplicate)
 	pr.Next = pr.Match + 1
+	pr.pendingCommit = min(pr.pendingCommit, pr.Match)
 }
 
 // BecomeSnapshot moves the Progress to StateSnapshot with the specified pending
@@ -143,31 +153,45 @@ func (pr *Progress) BecomeSnapshot(snapshoti uint64) {
 	pr.PendingSnapshot = snapshoti
 }
 
-// UpdateOnEntriesSend updates the progress on the given number of consecutive
-// entries being sent in a MsgApp, with the given total bytes size, appended at
-// log indices >= pr.Next.
+// SentEntries updates the progress on the given number of consecutive entries
+// being sent in a MsgApp, with the given total bytes size, appended at log
+// indices >= pr.Next.
 //
 // Must be used with StateProbe or StateReplicate.
-func (pr *Progress) UpdateOnEntriesSend(entries int, bytes uint64) {
-	switch pr.State {
-	case StateReplicate:
-		if entries > 0 {
-			pr.Next += uint64(entries)
-			pr.Inflights.Add(pr.Next-1, bytes)
-		}
-		// If this message overflows the in-flights tracker, or it was already full,
-		// consider this message being a probe, so that the flow is paused.
-		pr.MsgAppFlowPaused = pr.Inflights.Full()
-	case StateProbe:
-		// TODO(pavelkalinnikov): this condition captures the previous behaviour,
-		// but we should set MsgAppFlowPaused unconditionally for simplicity, because any
-		// MsgApp in StateProbe is a probe, not only non-empty ones.
-		if entries > 0 {
-			pr.MsgAppFlowPaused = true
-		}
-	default:
-		panic(fmt.Sprintf("sending append in unhandled state %s", pr.State))
+func (pr *Progress) SentEntries(entries int, bytes uint64) {
+	if pr.State == StateReplicate && entries > 0 {
+		pr.Next += uint64(entries)
+		pr.Inflights.Add(pr.Next-1, bytes)
 	}
+	pr.PauseMsgAppProbes(true)
+}
+
+// PauseMsgAppProbes pauses or unpauses empty MsgApp messages flow, depending on
+// the passed-in bool.
+func (pr *Progress) PauseMsgAppProbes(pause bool) {
+	pr.MsgAppProbesPaused = pause
+}
+
+// CanSendEntries returns true if the flow control state allows sending at least
+// one log entry to this follower.
+//
+// Must be used with StateProbe or StateReplicate.
+func (pr *Progress) CanSendEntries(lastIndex uint64) bool {
+	return pr.Next <= lastIndex && (pr.State == StateProbe || !pr.Inflights.Full())
+}
+
+// CanBumpCommit returns true if sending the given commit index can potentially
+// advance the follower's commit index.
+func (pr *Progress) CanBumpCommit(index uint64) bool {
+	return pr.pendingCommit < min(index, pr.Next-1)
+}
+
+// SentCommit updates the pendingCommit.
+func (pr *Progress) SentCommit(commit uint64) {
+	// Sending the given commit index may bump the follower's commit index up to
+	// Next-1, or even higher. We track only up to Next-1, and maintain the
+	// invariant: pendingCommit < Next.
+	pr.pendingCommit = min(max(pr.pendingCommit, commit), pr.Next-1)
 }
 
 // MaybeUpdate is called when an MsgAppResp arrives from the follower, with the
@@ -179,7 +203,6 @@ func (pr *Progress) MaybeUpdate(n uint64) bool {
 	}
 	pr.Match = n
 	pr.Next = max(pr.Next, n+1) // invariant: Match < Next
-	pr.MsgAppFlowPaused = false
 	return true
 }
 
@@ -205,6 +228,7 @@ func (pr *Progress) MaybeDecrTo(rejected, matchHint uint64) bool {
 		//
 		// TODO(tbg): why not use matchHint if it's larger?
 		pr.Next = pr.Match + 1
+		pr.pendingCommit = min(pr.pendingCommit, pr.Match)
 		return true
 	}
 
@@ -216,7 +240,8 @@ func (pr *Progress) MaybeDecrTo(rejected, matchHint uint64) bool {
 	}
 
 	pr.Next = max(min(rejected, matchHint+1), pr.Match+1)
-	pr.MsgAppFlowPaused = false
+	pr.pendingCommit = min(pr.pendingCommit, pr.Next-1)
+	pr.PauseMsgAppProbes(false)
 	return true
 }
 
@@ -226,12 +251,17 @@ func (pr *Progress) MaybeDecrTo(rejected, matchHint uint64) bool {
 // operation, this is false. A throttled node will be contacted less frequently
 // until it has reached a state in which it's able to accept a steady stream of
 // log entries again.
+//
+// TODO(pav-kv): this method is deprecated, remove it. It is still used in tests
+// and String(), find a way to avoid this. The problem is that the actual flow
+// control state depends on the log size and commit index, which are not part of
+// this Progress struct - they are passed-in to methods like ShouldSendMsgApp().
 func (pr *Progress) IsPaused() bool {
 	switch pr.State {
 	case StateProbe:
-		return pr.MsgAppFlowPaused
+		return pr.MsgAppProbesPaused
 	case StateReplicate:
-		return pr.MsgAppFlowPaused
+		return pr.MsgAppProbesPaused && pr.Inflights.Full()
 	case StateSnapshot:
 		return true
 	default:
@@ -239,6 +269,39 @@ func (pr *Progress) IsPaused() bool {
 	}
 }
 
+// ShouldSendMsgApp returns true if the leader should send a MsgApp to the
+// follower represented by this Progress. The given last and commit index of the
+// leader log help determining if there is outstanding workload, and contribute
+// to this decision-making.
+//
+// In StateProbe, a message is sent periodically. The flow is paused after every
+// message, and un-paused on a heartbeat response. This ensures that probes are
+// not too frequent, and eventually the MsgApp is either accepted or rejected.
+//
+// In StateReplicate, generally a message is sent if there are log entries that
+// are not yet in-flight, and the in-flight limits are not exceeded. Otherwise,
+// we don't send a message, or send a "probe" message in a few situations.
+//
+// A probe message (containing no log entries) is sent if the follower's commit
+// index can be updated, or there hasn't been a probe message recently. We must
+// send a message periodically even if all log entries are in-flight, in order
+// to guarantee that eventually the flow is either accepted or rejected.
+//
+// In StateSnapshot, we do not send append messages.
+func (pr *Progress) ShouldSendMsgApp(last, commit uint64) bool {
+	switch pr.State {
+	case StateProbe:
+		return !pr.MsgAppProbesPaused
+	case StateReplicate:
+		return pr.CanBumpCommit(commit) ||
+			pr.Match < last && (!pr.MsgAppProbesPaused || pr.CanSendEntries(last))
+	case StateSnapshot:
+		return false
+	default:
+		panic("unexpected state")
+	}
+}
+
 func (pr *Progress) String() string {
 	var buf strings.Builder
 	fmt.Fprintf(&buf, "%s match=%d next=%d", pr.State, pr.Match, pr.Next)
diff --git a/tracker/progress_test.go b/tracker/progress_test.go
index 49dedb53..c9485c21 100644
--- a/tracker/progress_test.go
+++ b/tracker/progress_test.go
@@ -24,14 +24,14 @@ func TestProgressString(t *testing.T) {
 	ins := NewInflights(1, 0)
 	ins.Add(123, 1)
 	pr := &Progress{
-		Match:            1,
-		Next:             2,
-		State:            StateSnapshot,
-		PendingSnapshot:  123,
-		RecentActive:     false,
-		MsgAppFlowPaused: true,
-		IsLearner:        true,
-		Inflights:        ins,
+		Match:              1,
+		Next:               2,
+		State:              StateSnapshot,
+		PendingSnapshot:    123,
+		RecentActive:       false,
+		MsgAppProbesPaused: true,
+		IsLearner:          true,
+		Inflights:          ins,
 	}
 	const exp = `StateSnapshot match=1 next=2 learner paused pendingSnap=123 inactive inflight=1[full]`
 	assert.Equal(t, exp, pr.String())
@@ -47,32 +47,35 @@ func TestProgressIsPaused(t *testing.T) {
 		{StateProbe, false, false},
 		{StateProbe, true, true},
 		{StateReplicate, false, false},
-		{StateReplicate, true, true},
+		{StateReplicate, true, false},
 		{StateSnapshot, false, true},
 		{StateSnapshot, true, true},
 	}
 	for i, tt := range tests {
 		p := &Progress{
-			State:            tt.state,
-			MsgAppFlowPaused: tt.paused,
-			Inflights:        NewInflights(256, 0),
+			State:              tt.state,
+			MsgAppProbesPaused: tt.paused,
+			Inflights:          NewInflights(256, 0),
 		}
 		assert.Equal(t, tt.w, p.IsPaused(), i)
 	}
 }
 
-// TestProgressResume ensures that MaybeUpdate and MaybeDecrTo will reset
-// MsgAppFlowPaused.
+// TestProgressResume ensures that MaybeDecrTo resets MsgAppProbesPaused, and
+// MaybeUpdate does not.
+//
+// TODO(pav-kv): there is little sense in testing these micro-behaviours in the
+// struct. We should test the visible behaviour instead.
 func TestProgressResume(t *testing.T) {
 	p := &Progress{
-		Next:             2,
-		MsgAppFlowPaused: true,
+		Next:               2,
+		MsgAppProbesPaused: true,
 	}
 	p.MaybeDecrTo(1, 1)
-	assert.False(t, p.MsgAppFlowPaused)
-	p.MsgAppFlowPaused = true
+	assert.False(t, p.MsgAppProbesPaused)
+	p.MsgAppProbesPaused = true
 	p.MaybeUpdate(2)
-	assert.False(t, p.MsgAppFlowPaused)
+	assert.True(t, p.MsgAppProbesPaused)
 }
 
 func TestProgressBecomeProbe(t *testing.T) {