Promise already completed in AkkaNettyGrpcClientGraphStage

[johanandren]

Unclear what the circumstances were, but here is the stack trace:

java.lang.IllegalStateException: Promise already completed.
	at scala.concurrent.Promise.complete(Promise.scala:57)
	at scala.concurrent.Promise.complete$(Promise.scala:56)
	at scala.concurrent.impl.Promise$DefaultPromise.complete(Promise.scala:104)
	at scala.concurrent.Promise.success(Promise.scala:91)
	at scala.concurrent.Promise.success$(Promise.scala:91)
	at scala.concurrent.impl.Promise$DefaultPromise.success(Promise.scala:104)
	at akka.grpc.internal.AkkaNettyGrpcClientGraphStage$$anon$1$$anon$2.onHeaders(AkkaNettyGrpcClientGraphStage.scala:88)
	at akka.grpc.internal.AkkaNettyGrpcClientGraphStage$$anon$1$$anon$2.onClose(AkkaNettyGrpcClientGraphStage.scala:107)
	at io.grpc.internal.DelayedClientCall$DelayedListener$3.run(DelayedClientCall.java:489)
	at io.grpc.internal.DelayedClientCall$DelayedListener.delayOrExecute(DelayedClientCall.java:453)
	at io.grpc.internal.DelayedClientCall$DelayedListener.onClose(DelayedClientCall.java:486)
	at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:564)
	at io.grpc.internal.ClientCallImpl.access$100(ClientCallImpl.java:72)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInternal(ClientCallImpl.java:729)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:710)
	at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
	at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)