code: func (svc Service) String() string {
  	switch {
  	case svc.FirewallMark > 0:
  		return fmt.Sprintf("FWM %d (%s)", svc.FirewallMark, svc.Scheduler)
  	case svc.Address.To4() == nil:
  		return fmt.Sprintf("%v [%v]:%d (%s)", svc.Protocol, svc.Address, svc.Port, svc.Scheduler)
  	default:
  		return fmt.Sprintf("%v %v:%d (%s)", svc.Protocol, svc.Address, svc.Port, svc.Scheduler)
  	}
  }
docs: // String returns a string representation of a Service.