server.ref()


unref() 相反,如果它是唯一剩下的服务器(默认行为),则在以前的 unref 的服务器上调用 ref() 不会让程序退出。 如果服务器被 ref,则再次调用 ref() 将无效。

Opposite of unref(), calling ref() on a previously unrefed server will not let the program exit if it's the only server left (the default behavior). If the server is refed calling ref() again will have no effect.