此符号应用于安装仅监视 'error' 事件的监听器。 在调用常规 'error' 监听器之前调用使用此符号安装的监听器。

This symbol shall be used to install a listener for only monitoring 'error' events. Listeners installed using this symbol are called before the regular 'error' listeners are called.

Installing a listener using this symbol does not change the behavior once an 'error' event is emitted. Therefore, the process will still crash if no regular 'error' listener is installed.