feat: unstable dynamic routing feature

ic-agent/Cargo.toml

@@ -15,7 +15,11 @@ keywords = ["internet-computer", "agent", "icp", "dfinity"]
 include = ["src", "Cargo.toml", "../LICENSE", "README.md"]
 
 [dependencies]
+arc-swap = { version = "1.7", optional = true }
+async-channel = { version = "1.9", optional = true }
 async-lock = "3.3"
+async-trait = { version = "0.1", optional = true }
+async-watch = { version = "0.3", optional = true }
 backoff = "0.4.0"
 cached = { version = "0.52", features = ["ahash"], default-features = false }
 candid = { workspace = true }
@@ -41,8 +45,10 @@ serde_cbor = { workspace = true }
 serde_repr = { workspace = true }
 sha2 = { workspace = true }
 simple_asn1 = "0.6.1"
+stop-token = { version = "0.7", optional = true }
 thiserror = { workspace = true }
 time = { workspace = true }
+tracing = { version = "0.1", optional = true }
 url = "2.1.0"
 
 [dependencies.reqwest]
@@ -67,6 +73,7 @@ web-sys = { version = "0.3", features = ["Window"], optional = true }
 
 [dev-dependencies]
 serde_json.workspace = true
+tracing-subscriber = "0.3"
 
 [target.'cfg(not(target_family = "wasm"))'.dev-dependencies]
 tokio = { workspace = true, features = ["full"] }
@@ -99,8 +106,17 @@ wasm-bindgen = [
     "backoff/wasm-bindgen",
     "cached/wasm",
 ]
+_internal_dynamic-routing = [
+    "dep:arc-swap",
+    "dep:async-channel",
+    "dep:async-trait",
+    "dep:async-watch",
+    "dep:stop-token",
+    "tracing",
+]
+tracing = ["dep:tracing"] # Does very little right now.
 
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu", "wasm32-unknown-unknown"]
 rustdoc-args = ["--cfg=docsrs"]
-features = ["hyper"]
+features = ["_internal_dynamic-routing"]

ic-agent/src/agent/route_provider.rs

@@ -7,6 +7,9 @@ use url::Url;
 
 use crate::agent::AgentError;
 
+#[cfg(feature = "_internal_dynamic-routing")]
+pub mod dynamic_routing;
+
 const IC0_DOMAIN: &str = "ic0.app";
 const ICP0_DOMAIN: &str = "icp0.io";
 const ICP_API_DOMAIN: &str = "icp-api.io";