code: func (h Host) Normalize() string {
  
  	s := string(h)
  
  	switch {
  	case strings.HasPrefix(s, TransportTLS+"://"):
  		s = s[len(TransportTLS+"://"):]
  	case strings.HasPrefix(s, TransportDNS+"://"):
  		s = s[len(TransportDNS+"://"):]
  	case strings.HasPrefix(s, TransportGRPC+"://"):
  		s = s[len(TransportGRPC+"://"):]
  	}
  
  	// The error can be ignore here, because this function is called after the corefile
  	// has already been vetted.
  	host, _, _, _ := SplitHostPort(s)
  	return Name(host).Normalize()
  }
docs: // Normalize will return the host portion of host, stripping
  // of any port or transport. The host will also be fully qualified and lowercased.