agent.keepSocketAlive(socket)

• socket <stream.Duplex>

当 socket 从请求中分离并且可以由 Agent 持久化时调用。 默认行为是：

socket.setKeepAlive(true, this.keepAliveMsecs);
socket.unref();
return true;

此方法可以被特定的 Agent 子类覆盖。 如果此方法返回假值，则套接字将被销毁，而不是将其持久化以供下一个请求使用。

socket 参数可以是 <net.Socket>（<stream.Duplex> 的子类）的实例。

• socket <stream.Duplex>

Called when socket is detached from a request and could be persisted by the Agent. Default behavior is to:

socket.setKeepAlive(true, this.keepAliveMsecs);
socket.unref();
return true;

This method can be overridden by a particular Agent subclass. If this method returns a falsy value, the socket will be destroyed instead of persisting it for use with the next request.

The socket argument can be an instance of <net.Socket>, a subclass of <stream.Duplex>.