'request' 事件

• request <http.IncomingMessage>
• response <http.ServerResponse>

每次有请求时触发。 每个连接可能有多个请求（在 HTTP Keep-Alive 连接的情况下）。

• request <http.IncomingMessage>
• response <http.ServerResponse>

Emitted each time there is a request. There may be multiple requests per connection (in the case of HTTP Keep-Alive connections).