socket.pipe(socket); 这个怎么解释

这样写的服务器，在客户端压力测试的时候警告

(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit. Trace at Socket.EventEmitter.addListener (events.js:175:15) at Socket.Stream.pipe (stream.js:85:10)