Add log info in case of enqueuing timeout

Author: acogoluegnes

src/main/java/com/rabbitmq/client/impl/NettyFrameHandlerFactory.java

@@ -51,6 +51,8 @@
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.time.Duration;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
@@ -438,9 +440,42 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
       }
     }
 
+    private static class Event {
+      private final long time;
+      private final String label;
+
+      public Event(long time, String label) {
+        this.time = time;
+        this.label = label;
+      }
+
+      @Override
+      public String toString() {
+        return this.label + " " + this.time;
+      }
+    }
+
+    private static final int MAX_EVENTS = 100;
+    private final Queue<Event> events = new ConcurrentLinkedQueue<>();
+
+    private void logEvents() {
+      if (this.events.size() > 0) {
+        long start = this.events.peek().time;
+        LOGGER.info("channel writability history:");
+        events.forEach(e -> LOGGER.info("{}: {}", (e.time - start) / 1_000_000, e.label));
+      }
+    }
+
     @Override
     public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
       boolean canWrite = ctx.channel().isWritable();
+      Event event = new Event(System.nanoTime(), Boolean.toString(canWrite));
+      if (this.events.size() >= MAX_EVENTS) {
+        this.events.poll();
+        this.events.offer(event);
+      }
+      this.events.add(event);
+
       if (this.writable.compareAndSet(!canWrite, canWrite)) {
         if (canWrite) {
           CountDownLatch latch = writableLatch.getAndSet(new CountDownLatch(1));