Add ResolutionEventListener#downloadMetadataSuccess to communicate long download times to consumers of MavenPomDownloader

rewrite-maven/src/main/java/org/openrewrite/maven/MavenExecutionContextView.java

@@ -23,8 +23,10 @@
 import org.openrewrite.maven.internal.MavenParsingException;
 import org.openrewrite.maven.tree.*;
 
+import java.net.URI;
 import java.time.Duration;
 import java.util.*;
+import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -48,6 +50,9 @@ public class MavenExecutionContextView extends DelegatingExecutionContext {
     private static final String MAVEN_RESOLUTION_LISTENER = "org.openrewrite.maven.resolutionListener";
     private static final String MAVEN_RESOLUTION_TIME = "org.openrewrite.maven.resolutionTime";
 
+    @Nullable
+    private  BiConsumer<URI, Duration> onDownloaded;
+
     public MavenExecutionContextView(ExecutionContext delegate) {
         super(delegate);
     }
@@ -238,6 +243,15 @@ public MavenExecutionContextView setMavenSettings(@Nullable MavenSettings settin
         return getMessage(MAVEN_SETTINGS, null);
     }
 
+    @Nullable
+    public BiConsumer<URI, Duration> getOnDownloaded() {
+        return onDownloaded;
+    }
+
+    public void setOnDownloaded(BiConsumer<URI, Duration> onDownloaded) {
+        this.onDownloaded = onDownloaded;
+    }
+
     private static List<String> mapActiveProfiles(MavenSettings settings, String... activeProfiles) {
         if (settings.getActiveProfiles() == null) {
             return Arrays.asList(activeProfiles);

rewrite-maven/src/main/java/org/openrewrite/maven/internal/MavenPomDownloader.java

@@ -55,7 +55,6 @@
 import static java.util.Objects.requireNonNull;
 import static java.util.stream.Collectors.toList;
 
-@SuppressWarnings("OptionalAssignedToNull")
 public class MavenPomDownloader {
     private static final RetryPolicy<Object> retryPolicy = RetryPolicy.builder()
             .handle(SocketTimeoutException.class, TimeoutException.class)
@@ -333,7 +332,12 @@ public MavenMetadata downloadMetadata(GroupArtifactVersion gav, @Nullable Resolv
                     .setRepositoryResponses(repositoryResponses);
         }
 
-        sample.stop(timer.tags("outcome", "success").register(Metrics.globalRegistry));
+        long nanos = sample.stop(timer.tags("outcome", "success").register(Metrics.globalRegistry));
+        if (ctx.getOnDownloaded() != null) {
+            ctx.getOnDownloaded().accept(
+                    URI.create(attemptedUris.get(attemptedUris.size() - 1)),
+                    Duration.ofNanos(nanos));
+        }
         return mavenMetadata;
     }
 
@@ -604,6 +608,10 @@ public Pom download(GroupArtifactVersion gav,
                         mavenCache.putPom(resolvedGav, pom);
                         ctx.getResolutionListener().downloadSuccess(resolvedGav, containingPom);
                         sample.stop(timer.tags("outcome", "downloaded").register(Metrics.globalRegistry));
+                        long nanos = sample.stop(timer.tags("outcome", "downloaded").register(Metrics.globalRegistry));
+                        if (ctx.getOnDownloaded() != null) {
+                            ctx.getOnDownloaded().accept(uri, Duration.ofNanos(nanos));
+                        }
                         return pom;
                     } catch (HttpSenderResponseException e) {
                         repositoryResponses.put(repo, e.getMessage());