http.ResponseWriter的Flush

func handle(res http.ResponseWriter, req *http.Request) {
  fmt.Fprintf(res, "sending first line of data")
  sleep(10) 
  fmt.Fprintf(res, "sending second line of data")
}
这样first data和second data都会最后同时传到客户端浏览器。但是我们的目的是为了能一有数据就先传给浏览器。所以：

func handle(res http.ResponseWriter, req *http.Request) {
  fmt.Fprintf(res, "sending first line of data")

  res.(http.Flusher).Flush()

  sleep(10)

  fmt.Fprintf(res, "sending second line of data")
}

资料：

https://stackoverflow.com/questions/19292113/not-buffered-http-responsewritter-in-golang