refactor: add set event stream headers func (#402)

封装流式传输响应头的设置

controller/relay-zhipu.go

@@ -224,11 +224,7 @@ func zhipuStreamHandler(c *gin.Context, resp *http.Response) (*OpenAIErrorWithSt
 		}
 		stopChan <- true
 	}()
-	c.Writer.Header().Set("Content-Type", "text/event-stream")
-	c.Writer.Header().Set("Cache-Control", "no-cache")
-	c.Writer.Header().Set("Connection", "keep-alive")
-	c.Writer.Header().Set("Transfer-Encoding", "chunked")
-	c.Writer.Header().Set("X-Accel-Buffering", "no")
+	setEventStreamHeaders(c)
 	c.Stream(func(w io.Writer) bool {
 		select {
 		case data := <-dataChan: