事件:'socket'
【Event: 'socket'】
socket<stream.Duplex>
此事件保证会传递一个 <net.Socket> 类的实例,该类是 <stream.Duplex> 的子类,除非用户指定了其他类型的套接字而不是 <net.Socket>。
【This event is guaranteed to be passed an instance of the <net.Socket> class, a subclass of <stream.Duplex>, unless the user specifies a socket type other than <net.Socket>.】