UNKNOWN: missing GRPC status in response when using Cronet + QUIC

[mxalbert1996]

What version of gRPC-Java are you using?

1.78.0

What is your environment?

Server: Cloudflare with HTTP/3 enabled
Client: Android 16 / gRPC with CronetChannelBuilder

What did you expect to see?

gRPC works properly.

What did you see instead?

gRPC fails with the following exception.

io.grpc.StatusException: UNKNOWN: missing GRPC status in response
	at io.grpc.Status.asException(Status.java:547)
	at io.grpc.kotlin.ClientCalls$rpcImpl$1$1$1.onClose(ClientCalls.kt:264)
	at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:566)
	at io.grpc.internal.ClientCallImpl.access$100(ClientCallImpl.java:72)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInternal(ClientCallImpl.java:734)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:715)
	at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
	at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
	at kotlinx.coroutines.internal.LimitedDispatcher$Worker.run(LimitedDispatcher.kt:124)
	at kotlinx.coroutines.scheduling.TaskImpl.run(Tasks.kt:89)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:586)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:820)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:717)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:704)

This issue doesn't always happen, and when I logged the protocols of the requests (RequestFinishedInfo.getResponseInfo().getNegotiatedProtocol()) by CronetEngine.addRequestFinishedListener(), I found that all the successful request were using h2 protocol, and all the failed requests were using quic/1+spdy/3.

Steps to reproduce the bug

Use CronetChannelBuilder to request a backend with QUIC enabled.

[mxalbert1996]

As per https://groups.google.com/g/grpc-io/c/ogqs3WWhed4/m/9y44vUk2FAAJ, QUIC is supported via Cronet in gRPC Java, but I had to disable QUIC on the CronetEngine for gRPC to work.