code: func (s *ServiceRecord) ServiceName() string {
  	if s.serviceName == "" {
  		s.serviceName = fmt.Sprintf("%s.%s.", trimDot(s.Service), trimDot(s.Domain))
  	}
  	return s.serviceName
  }
docs: // Returns complete service name (e.g. _foobar._tcp.local.), which is composed
  // from a service name (also referred as service type) and a domain.