code: func (r *Result) String() string {
  	var str string
  	if r.IP4 != nil {
  		str = fmt.Sprintf("IP4:%+v, ", *r.IP4)
  	}
  	if r.IP6 != nil {
  		str += fmt.Sprintf("IP6:%+v, ", *r.IP6)
  	}
  	return fmt.Sprintf("%sDNS:%+v", str, r.DNS)
  }
docs: // String returns a formatted string in the form of "[IP4: $1,][ IP6: $2,] DNS: $3" where
  // $1 represents the receiver's IPv4, $2 represents the receiver's IPv6 and $3 the
  // receiver's DNS. If $1 or $2 are nil, they won't be present in the returned string.