after(asyncId)

在 before 中指定的回调完成后立即调用。

¥Called immediately after the callback specified in before is completed.

如果在执行回调期间发生未捕获的异常，则 after 将在 'uncaughtException' 事件触发或 domain 的处理程序运行后运行。

¥If an uncaught exception occurs during execution of the callback, then after will run after the 'uncaughtException' event is emitted or a domain's handler runs.