code: func predictAddr(t *netutil.IPTracker) (net.IP, int) {
  	ep := t.PredictEndpoint()
  	if ep == "" {
  		return nil, 0
  	}
  	ipString, portString, _ := net.SplitHostPort(ep)
  	ip := net.ParseIP(ipString)
  	port, _ := strconv.Atoi(portString)
  	return ip, port
  }
docs: // predictAddr wraps IPTracker.PredictEndpoint, converting from its string-based
  // endpoint representation to IP and port types.