socket.localAddress
远程客户端连接的本地 IP 地址字符串。例如，一个服务端正在连接到 '0.0.0.0'，客户端连接到的是 '192.168.1.1'，则 socket.localAddress 的值是 '192.168.1.1'。
The string representation of the local IP address the remote client is
connecting on. For example, in a server listening on '0.0.0.0', if a client
connects on '192.168.1.1', the value of socket.localAddress would be
'192.168.1.1'.