implement WebSocketRequestHandler.exceptionCaught()

[blavenie]

Error in log file :

[2019-10-08 10:35:57,368][WARN ][netty.channel.SimpleChannelHandler] EXCEPTION, please implement org.duniter.elasticsearch.http.netty.WebSocketRequestHandler.exceptionCaught() for proper ha
ndling.
java.io.IOException: Broken pipe
        at sun.nio.ch.FileDispatcherImpl.write0(Native Method)
        at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:47)
        at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:93)
        at sun.nio.ch.IOUtil.write(IOUtil.java:51)
        at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:471)
        at org.jboss.netty.channel.socket.nio.SocketSendBufferPool$UnpooledSendBuffer.transferTo(SocketSendBufferPool.java:203)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.write0(AbstractNioWorker.java:201)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.writeFromUserCode(AbstractNioWorker.java:146)
        at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.handleAcceptedSocket(NioServerSocketPipelineSink.java:99)
        at org.jboss.netty.channel.socket.nio.NioServerSocketPipelineSink.eventSunk(NioServerSocketPipelineSink.java:36)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendDownstream(DefaultChannelPipeline.java:779)
        at org.jboss.netty.channel.Channels.write(Channels.java:725)
        at org.jboss.netty.handler.codec.oneone.OneToOneEncoder.doEncode(OneToOneEncoder.java:71)
        at org.jboss.netty.handler.codec.oneone.OneToOneEncoder.handleDownstream(OneToOneEncoder.java:59)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendDownstream(DefaultChannelPipeline.java:591)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendDownstream(DefaultChannelPipeline.java:784)
        at org.jboss.netty.channel.SimpleChannelHandler.writeRequested(SimpleChannelHandler.java:292)
        at org.jboss.netty.channel.SimpleChannelHandler.handleDownstream(SimpleChannelHandler.java:254)
        at org.elasticsearch.http.netty.pipelining.HttpPipeliningHandler.handleDownstream(HttpPipeliningHandler.java:105)
        at org.jboss.netty.channel.DefaultChannelPipeline.sendDownstream(DefaultChannelPipeline.java:591)
        at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendDownstream(DefaultChannelPipeline.java:784)
        at org.jboss.netty.channel.SimpleChannelHandler.writeRequested(SimpleChannelHandler.java:292)
        at org.jboss.netty.channel.SimpleChannelHandler.handleDownstream(SimpleChannelHandler.java:254)