response.finished
稳定性: 0 - 弃用. 改为使用
response.writableEnded.指示响应是否已完成的布尔值。
从 false 开始。
在 response.end() 执行后，值为 true。
Stability: 0 - Deprecated. Use
response.writableEnded.Boolean value that indicates whether the response has completed. Starts
as false. After response.end() executes, the value will be true.