Handle subscription init timeout gracefully

[pdambrauskas]

📝 Description

When using Spring Server client tries to initiate subscription, but timeout occurs before sending connection_init message Kotlin coroutine fails with exception:

2024-01-22T11:14:05.757+02:00  INFO 20308 --- [           main] c.p.ApplicationKt   : Started ApplicationKt in 2.86 seconds (process running for 3.29)
Exception in thread "DefaultDispatcher-worker-2" java.util.NoSuchElementException: No value received via onNext for awaitFirst
	at kotlinx.coroutines.reactive.AwaitKt$awaitOne$2$1.onComplete(Await.kt:282)
	at reactor.core.publisher.StrictSubscriber.onComplete(StrictSubscriber.java:123)
	at reactor.core.publisher.FluxPeek$PeekSubscriber.onComplete(FluxPeek.java:260)
	at reactor.netty.FutureMono$FutureSubscription.operationComplete(FutureMono.java:196)
	at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:590)
	at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:583)
	at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:559)
	at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:492)
	at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:636)
	at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:625)
	at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:105)
	at io.netty.util.internal.PromiseNotificationUtil.trySuccess(PromiseNotificationUtil.java:48)
	at io.netty.channel.ChannelOutboundBuffer.safeSuccess(ChannelOutboundBuffer.java:726)
	at io.netty.channel.ChannelOutboundBuffer.remove(ChannelOutboundBuffer.java:281)
	at io.netty.channel.ChannelOutboundBuffer.removeBytes(ChannelOutboundBuffer.java:361)
	at io.netty.channel.socket.nio.NioSocketChannel.doWrite(NioSocketChannel.java:421)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.flush0(AbstractChannel.java:931)
	at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.flush0(AbstractNioChannel.java:355)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.flush(AbstractChannel.java:895)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.flush(DefaultChannelPipeline.java:1372)
	at io.netty.channel.AbstractChannelHandlerContext.invokeFlush0(AbstractChannelHandlerContext.java:921)
	at io.netty.channel.AbstractChannelHandlerContext.invokeFlush(AbstractChannelHandlerContext.java:907)
	at io.netty.channel.AbstractChannelHandlerContext.flush(AbstractChannelHandlerContext.java:893)
	at io.netty.channel.ChannelOutboundHandlerAdapter.flush(ChannelOutboundHandlerAdapter.java:125)
	at io.netty.channel.AbstractChannelHandlerContext.invokeFlush0(AbstractChannelHandlerContext.java:925)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:941)
	at io.netty.channel.AbstractChannelHandlerContext$WriteTask.run(AbstractChannelHandlerContext.java:1247)
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:1583)
	Suppressed: kotlinx.coroutines.internal.DiagnosticCoroutineContextException: [StandaloneCoroutine{Cancelling}@2f9aebd2, Dispatchers.Default]

This small change fixes the problem, I've also added a test to cover this specific case.