事件：'unpipe'

¥Event: 'unpipe'

• src <stream.Readable> unpiped 这个可写的源码流

  ¥src <stream.Readable> The source stream that unpiped this writable

当在 Readable 流上调用 stream.unpipe() 方法时，则会触发 'unpipe' 事件，从其目标集合中删除此 Writable。

¥The 'unpipe' event is emitted when the stream.unpipe() method is called on a Readable stream, removing this Writable from its set of destinations.

当 Readable 流管道进入它时，如果此 Writable 流触发错误，则这也会触发。

¥This is also emitted in case this Writable stream emits an error when a Readable stream pipes into it.

const writer = getWritableStreamSomehow();
const reader = getReadableStreamSomehow();
writer.on('unpipe', (src) => {
  console.log('Something has stopped piping into the writer.');
  assert.equal(src, reader);
});
reader.pipe(writer);
reader.unpipe(writer); 拷贝