timeout.ref()

• 返回：<Timeout> 对 timeout 的引用

当被调用时，会请求 Node.js 事件循环在 Timeout 活跃期间保持运行。多次调用 timeout.ref() 不会有任何效果。

🌐 When called, requests that the Node.js event loop not exit so long as the Timeout is active. Calling timeout.ref() multiple times will have no effect.

默认情况下，所有 Timeout 对象都是被“引用”的，通常不需要调用 timeout.ref()，除非之前已调用过 timeout.unref()。

🌐 By default, all Timeout objects are "ref'ed", making it normally unnecessary to call timeout.ref() unless timeout.unref() had been called previously.