after(asyncId)

在 before 中指定的回调完成后立即调用。

如果在回调执行期间发生未捕获的异常，则 after 将在 'uncaughtException' 事件触发或 domain 的句柄运行之后运行。

Called immediately after the callback specified in before is completed.

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.