code: func logger(ww *ResponseWriter, r *http.Request) {
  	log.Printf("%s [%s] %d %d %s %s",
  		r.RemoteAddr,
  		r.URL,
  		ww.Status(),
  		ww.Size(),
  		ww.RequestTime(),
  		ww.RequestID())
  }
docs: // logger log values separated by space