Reduce log level for WebSocket connections closed by clients

[sbordet]

Jetty version
9.4.x

Description

This seems a client-side close that we don't need to report at WARN level - it just fills up the logs.

2020-12-10 01:53:28.932:WARN:oejwcec.CompressExtension:qtp1218416846-1412: 
java.nio.channels.ClosedChannelException
	at org.eclipse.jetty.websocket.common.io.FrameFlusher.enqueue(FrameFlusher.java:109)
	at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.outgoingFrame(AbstractWebSocketConnection.java:579)
	at org.eclipse.jetty.websocket.common.extensions.AbstractExtension.nextOutgoingFrame(AbstractExtension.java:157)
	at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.nextOutgoingFrame(PerMessageDeflateExtension.java:125)
	at org.eclipse.jetty.websocket.common.extensions.compress.CompressExtension.access$1100(CompressExtension.java:44)
	at org.eclipse.jetty.websocket.common.extensions.compress.CompressExtension$Flusher.compress(CompressExtension.java:579)
	at org.eclipse.jetty.websocket.common.extensions.compress.CompressExtension$Flusher.deflate(CompressExtension.java:478)
	at org.eclipse.jetty.websocket.common.extensions.compress.CompressExtension$Flusher.process(CompressExtension.java:458)
	at org.eclipse.jetty.util.IteratingCallback.processing(IteratingCallback.java:241)
	at org.eclipse.jetty.util.IteratingCallback.iterate(IteratingCallback.java:223)
	at org.eclipse.jetty.websocket.common.extensions.compress.CompressExtension.outgoingFrame(CompressExtension.java:241)
	at org.eclipse.jetty.websocket.common.extensions.ExtensionStack$Flusher.process(ExtensionStack.java:403)
	at org.eclipse.jetty.util.IteratingCallback.processing(IteratingCallback.java:241)
	at org.eclipse.jetty.util.IteratingCallback.iterate(IteratingCallback.java:223)
	at org.eclipse.jetty.websocket.common.extensions.ExtensionStack.outgoingFrame(ExtensionStack.java:280)
	at org.eclipse.jetty.websocket.common.WebSocketSession.outgoingFrame(WebSocketSession.java:360)
	at org.eclipse.jetty.websocket.common.WebSocketRemoteEndpoint.uncheckedSendFrame(WebSocketRemoteEndpoint.java:322)
	at org.eclipse.jetty.websocket.jsr356.JsrAsyncRemote.sendText(JsrAsyncRemote.java:188)
	at org.cometd.websocket.server.WebSocketTransport.send(WebSocketTransport.java:117)
	at org.cometd.websocket.server.WebSocketTransport.send(WebSocketTransport.java:51)
	at org.cometd.websocket.server.common.AbstractWebSocketTransport$AbstractWebSocketScheduler.send(AbstractWebSocketTransport.java:195)
	at org.cometd.websocket.server.common.AbstractWebSocketTransport$AbstractWebSocketScheduler$Flusher.process(AbstractWebSocketTransport.java:586)
	at org.eclipse.jetty.util.IteratingCallback.processing(IteratingCallback.java:241)
	at org.eclipse.jetty.util.IteratingCallback.iterate(IteratingCallback.java:223)
	at org.cometd.websocket.server.common.AbstractWebSocketTransport$AbstractWebSocketScheduler.send(AbstractWebSocketTransport.java:412)
	at org.cometd.websocket.server.common.AbstractWebSocketTransport$AbstractWebSocketScheduler.processMessages(AbstractWebSocketTransport.java:336)
	at org.cometd.websocket.server.common.AbstractWebSocketTransport$AbstractWebSocketScheduler.onMessage(AbstractWebSocketTransport.java:244)
	at org.cometd.websocket.server.WebSocketTransport$WebSocketScheduler.onMessage(WebSocketTransport.java:193)
	at org.cometd.websocket.server.WebSocketTransport$WebSocketScheduler.onMessage(WebSocketTransport.java:131)
	at org.eclipse.jetty.websocket.jsr356.messages.TextWholeMessage.messageComplete(TextWholeMessage.java:59)
	at org.eclipse.jetty.websocket.jsr356.endpoints.JsrEndpointEventDriver.onTextFrame(JsrEndpointEventDriver.java:228)
	at org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:152)
	at org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:326)
	at org.eclipse.jetty.websocket.common.extensions.AbstractExtension.nextIncomingFrame(AbstractExtension.java:148)
	at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.nextIncomingFrame(PerMessageDeflateExtension.java:113)
	at org.eclipse.jetty.websocket.common.extensions.compress.CompressExtension.forwardIncoming(CompressExtension.java:168)
	at org.eclipse.jetty.websocket.common.extensions.compress.PerMessageDeflateExtension.incomingFrame(PerMessageDeflateExtension.java:92)
	at org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:202)
	at org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:225)
	at org.eclipse.jetty.websocket.common.Parser.parseSingleFrame(Parser.java:259)
	at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:459)
	at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:440)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
	at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:375)
	at org.eclipse.jetty.util.thread.MonitoredQueuedThreadPool$1.run(MonitoredQueuedThreadPool.java:77)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:773)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:905)
	at java.base/java.lang.Thread.run(Thread.java:834)