code: func randoHandler(w http.ResponseWriter, r *http.Request) {
  	delay := rand.Intn(5000)
  	var code int
  	switch rand.Intn(10) {
  	case 0:
  		code = 404
  	case 1:
  		code = 400
  	case 2:
  		code = 501
  	case 3:
  		code = 500
  	default:
  		code = 200
  	}
  
  	log.Printf("incoming request on :9000 - will return %d in %d ms", code, delay)
  
  	<-time.Tick(time.Duration(delay) * time.Millisecond)
  
  	w.WriteHeader(code)
  	w.Write([]byte(http.StatusText(code)))
  }
docs: // randoHandler will cause random delays and give random status responses