code: func (a Address) String() string {
  	if a.Host == "" && a.Port == "" {
  		return ""
  	}
  	scheme := a.Scheme
  	if scheme == "" {
  		if a.Port == "443" {
  			scheme = "https"
  		} else {
  			scheme = "http"
  		}
  	}
  	s := scheme
  	if s != "" {
  		s += "://"
  	}
  	s += a.Host
  	if a.Port != "" &&
  		((scheme == "https" && a.Port != "443") ||
  			(scheme == "http" && a.Port != "80")) {
  		s += ":" + a.Port
  	}
  	if a.Path != "" {
  		s += a.Path
  	}
  	return s
  }
docs: // String returns a human-friendly print of the address.