code: func computeApproximateRequestSize(r *http.Request) int64 {
  	s := 0
  	if r.URL != nil {
  		s += len(r.URL.String())
  	}
  	s += len(r.Method)
  	s += len(r.Proto)
  	s += len(r.Host)
  
  	hs := 0
  	for name, values := range r.Header {
  		hs += len(name)
  		for _, value := range values {
  			hs += len(value)
  		}
  	}
  	s += hs
  
  	// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
  
  	var size int64
  	size = int64(s)
  	if r.ContentLength != -1 {
  		size += r.ContentLength
  	}
  	log.Debug(nil, map[string]interface{}{
  		"header_size": hs, "body_size": r.ContentLength, "req_size": size},
  		"compute request size")
  	return size
  }
docs: // TODO http2 request not supported