No concurrent request handling

[ahmetb]

Using your code, if I make a handler like:

func handler(w http.ResponseWriter, r *http.Request) {
	time.Sleep(time.Second * 5)
	fmt.Fprintf(w, "This request is served over h2c!")
}

and make two requests at the same time, one returns in 5 seconds, the other one returns in 10 seconds.

I think you need a go statement like go server.ServeConn in the example code.