response.statusMessage
- 类型：<string>
在使用隐式头（不显式调用 response.writeHead()）时，此属性控制在刷新头时将发送给客户端的状态消息。如果此项保持为 undefined，则使用状态码的标准消息。
【When using implicit headers (not calling response.writeHead() explicitly),
this property controls the status message that will be sent to the client when
the headers get flushed. If this is left as undefined then the standard
message for the status code will be used.】
response.statusMessage = 'Not found'; 在响应头发送给客户端之后，此属性表示已发送的状态消息。
【After response header was sent to the client, this property indicates the status message which was sent out.】