Log more info when inter-Node messaging fails.

Change-Id: Ifd749a3023854d688a675c7279c27868b8bed436

@@ -194,7 +194,7 @@ public class ClusterCommunicationManager
             try {
                 clusterMessage = SERIALIZER.decode(message.payload());
             } catch (Exception e) {
-                log.error("Failed decoding ClusterMessage", e);
+                log.error("Failed decoding ClusterMessage {}", message, e);
                 throw e;
             }
             try {

@@ -17,6 +17,10 @@ package org.onlab.netty;
 
 import java.io.IOException;
 
+import org.onlab.util.ByteArraySizeHashPrinter;
+
+import com.google.common.base.MoreObjects;
+
 /**
  * Internal message representation with additional attributes
  * for supporting, synchronous request/reply behavior.
@@ -73,6 +77,15 @@ public final class InternalMessage implements Message {
         messagingService.sendAsync(sender, message);
     }
 
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("id", id)
+                .add("type", type)
+                .add("sender", sender)
+                .add("payload", ByteArraySizeHashPrinter.of(payload))
+                .toString();
+    }
 
     /**
      * Builder for InternalMessages.