broadcastChannel.ref()

unref() 的相反。如果它是唯一剩下的活动句柄（默认行为），则在先前 unref() BroadcastChannel 上调用 ref() 不会让程序退出。如果端口是 ref() 的，则再次调用 ref() 没有效果。

¥Opposite of unref(). Calling ref() on a previously unref()ed BroadcastChannel does not let the program exit if it's the only active handle left (the default behavior). If the port is ref()ed, calling ref() again has no effect.