provider优雅停机，call需要30秒，consumer10秒后主动中断channel，导致优雅停机失败 #2952
Description
- I have searched the issues of this repository and believe that this is not a duplicate.
- I have checked the FAQ of this repository and believe that this is not a duplicate.
Environment
- Dubbo version: 2.6.5
- Operating System version: CentOS6.9
- Java version: 1.8
Steps to reproduce this issue
- provider server set JVM argument -Ddubbo.service.shutdown.wait=50000
- consumer call provider其中一个Service，需要30秒才能返回结果
3.after call 5秒后，执行 kill pid，将provider优雅停机
4.consumer收到register center发送的provider下线消息，主动关闭netty的channel连接
5.provider的DubboServerHandler线程30秒后想返回结果，发现channel关闭，抛出异常；
6.consumer端配置了60秒超时，得不到返回，抛出timeOut异常。导致请求异常结束
Pls. provide [GitHub address] to reproduce this issue.
Expected Result
What do you expected from the above steps？
期待结果是Service跑完30秒，正常返回，然后优雅停机。consumer端的后续请求切换到可用Service上
Actual Result
What actually happens?
If there is an exception, please attach the exception trace:
com.alibaba.dubbo.remoting.RemotingException: Failed to send message Response [id=213, version=2.0.2, status=20, event=false, error=null, result=RpcResult [返回的content], exception=null]] to /IP:65417, cause: null
at com.alibaba.dubbo.remoting.transport.netty.NettyChannel.send(NettyChannel.java:110) ~[dubbo-2.6.5.jar:2.6.5]
at com.alibaba.dubbo.remoting.transport.AbstractPeer.send(AbstractPeer.java:53) ~[dubbo-2.6.5.jar:2.6.5]
at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:174) ~[dubbo-2.6.5.jar:2.6.5]
at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:51) ~[dubbo-2.6.5.jar:2.6.5]
at com.alibaba.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:57) [dubbo-2.6.5.jar:2.6.5]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_45]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_45]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]
Caused by: java.nio.channels.ClosedChannelException
at org.jboss.netty.channel.socket.nio.NioWorker.cleanUpWriteBuffer(NioWorker.java:643) ~[netty-3.2.5.Final.jar:?]
at org.jboss.netty.channel.socket.nio.NioWorker.writeFromUserCode(NioWorker.java:370) ~[netty-3.2.5.Final.jar:?]
at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.handleAcceptedSocket(NioServerSocketPipelineSink.java:137) ~[netty-3.2.5.Final.jar:?]
at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.eventSunk(NioServerSocketPipelineSink.java:76) ~[netty-3.2.5.Final.jar:?]
at org.jboss.netty.channel.Channels.write(Channels.java:632) ~[netty-3.2.5.Final.jar:?]
at org.jboss.netty.handler.codec.oneone.OneToOneEncoder.handleDownstream(OneToOneEncoder.java:70) ~[netty-3.2.5.Final.jar:?]
at com.alibaba.dubbo.remoting.transport.netty.NettyHandler.writeRequested(NettyHandler.java:98) ~[dubbo-2.6.5.jar:2.6.5]
at org.jboss.netty.channel.Channels.write(Channels.java:611) ~[netty-3.2.5.Final.jar:?]
at org.jboss.netty.channel.Channels.write(Channels.java:578) ~[netty-3.2.5.Final.jar:?]
at org.jboss.netty.channel.AbstractChannel.write(AbstractChannel.java:251) ~[netty-3.2.5.Final.jar:?]
at com.alibaba.dubbo.remoting.transport.netty.NettyChannel.send(NettyChannel.java:100) ~[dubbo-2.6.5.jar:2.6.5]
... 7 more
最后发现问题，是consumer启动参数没有-Ddubbo.service.shutdown.wait=50000。当consumer端收到provider下线消息，主动触发一个优雅关闭链接，默认是10秒。加上参数后，就解决上面的问题。
但是provide的优雅关机居然需要comsumer配置，这可能是不合理的。所以看dubbo开发组怎么解决这个问题。
更多provider日志：
16:19:16.875 [DubboShutdownHook] INFO com.alibaba.dubbo.rpc.protocol.dubbo.DubboProtocol(432) - [DUBBO] Close dubbo server: /127.0.0.1:20881, dubbo version: 2.6.5, current host: 127.0.0.1
16:19:26.619 [New I/O server worker #1-1] WARN com.alibaba.dubbo.remoting.transport.AbstractServer(205) - [DUBBO] All clients has discontected from /127.0.0.1:20881. You can graceful shutdown now., dubbo version: 2.6.5, current host: 127.0.0.1