code: func (t *MockTransport) FinalAdvertiseAddr(string, int) (net.IP, int, error) {
  	host, portStr, err := net.SplitHostPort(t.addr.String())
  	if err != nil {
  		return nil, 0, err
  	}
  
  	ip := net.ParseIP(host)
  	if ip == nil {
  		return nil, 0, fmt.Errorf("Failed to parse IP %q", host)
  	}
  
  	port, err := strconv.ParseInt(portStr, 10, 16)
  	if err != nil {
  		return nil, 0, err
  	}
  
  	return ip, int(port), nil
  }
docs: // See Transport.