'close' 事件

当流或其底层资源(比如文件描述符)被关闭时触发。 表明不会再触发其他事件,也不会再发生操作。

不是所有可写流都会触发 'close' 事件。

The 'close' event is emitted when the stream and any of its underlying resources (a file descriptor, for example) have been closed. The event indicates that no more events will be emitted, and no further computation will occur.

A Writable stream will always emit the 'close' event if it is created with the emitClose option.