调用时,活动的 <fs.StatWatcher> 对象不需要 Node.js 事件循环保持活动状态。 如果没有其他活动保持事件循环运行,则进程可能会在调用 <fs.StatWatcher> 对象的回调之前退出。 多次调用 watcher.unref() 将不起作用。

When called, the active <fs.StatWatcher> object will not require the Node.js event loop to remain active. If there is no other activity keeping the event loop running, the process may exit before the <fs.StatWatcher> object's callback is invoked. Calling watcher.unref() multiple times will have no effect.