'timeout' 事件

当 socket 超时的时候触发。该事件只是用来通知 socket 已经闲置。用户必须手动关闭。

也可以查看：socket.setTimeout()

Emitted if the socket times out from inactivity. This is only to notify that the socket has been idle. The user must manually close the connection.

See also: socket.setTimeout().