GetClusterShardingStats needs java serialization

Akka Akka Cluster
1

when I set allow-java-serialization=false
then error occurred like below

2018-07-13 14:18:47,206+0900 ERROR [ka.actor.default-dispatcher-16]  akka.remote.EndpointWriter                         - Failed to serialize remote message [class akka.cluster.sharding.ShardRegion$GetShardRegionStats$] using serializer [class akka.serialization.DisabledJavaSerializer]. Transient association error (association remains live)
akka.remote.MessageSerializer$SerializationException: Failed to serialize remote message [class akka.cluster.sharding.ShardRegion$GetShardRegionStats$] using serializer [class akka.serialization.DisabledJavaSerializer].
	at akka.remote.MessageSerializer$.serialize(MessageSerializer.scala:62) ~[akka-remote_2.12-2.5.13.jar:2.5.13]
	at akka.remote.EndpointWriter.$anonfun$serializeMessage$1(Endpoint.scala:905) ~[akka-remote_2.12-2.5.13.jar:2.5.13]
	at scala.util.DynamicVariable.withValue(DynamicVariable.scala:58) ~[scala-library-2.12.6.jar:?]
	at akka.remote.EndpointWriter.serializeMessage(Endpoint.scala:905) ~[akka-remote_2.12-2.5.13.jar:2.5.13]
	at akka.remote.EndpointWriter.writeSend(Endpoint.scala:792) ~[akka-remote_2.12-2.5.13.jar:2.5.13]
	at akka.remote.EndpointWriter$$anonfun$4.applyOrElse(Endpoint.scala:767) ~[akka-remote_2.12-2.5.13.jar:2.5.13]
	at akka.actor.Actor.aroundReceive(Actor.scala:517) ~[akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.actor.Actor.aroundReceive$(Actor.scala:515) ~[akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.remote.EndpointActor.aroundReceive(Endpoint.scala:458) ~[akka-remote_2.12-2.5.13.jar:2.5.13]
	at akka.actor.ActorCell.receiveMessage(ActorCell.scala:588) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.actor.ActorCell.invoke(ActorCell.scala:557) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:258) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.dispatch.Mailbox.run(Mailbox.scala:225) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.dispatch.Mailbox.exec(Mailbox.scala:235) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [akka-actor_2.12-2.5.13.jar:2.5.13]
	at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [akka-actor_2.12-2.5.13.jar:2.5.13]
2

Seems to be an oversight. I created https://github.com/akka/akka/issues/25348 to track adding a protobuf serializer for it.