'finish' 事件

发送响应时触发。 更具体地说，当响应标头和正文的最后一段已移交给 HTTP/2 多路复用以通过网络传输时，则将触发此事件。 这并不意味着客户端已收到任何东西。

在此事件之后，响应对象上将不再触发更多事件。

Emitted when the response has been sent. More specifically, this event is emitted when the last segment of the response headers and body have been handed off to the HTTP/2 multiplexing for transmission over the network. It does not imply that the client has received anything yet.

After this event, no more events will be emitted on the response object.