code: func (n *NetworkServerAPI) SendProprietaryPayload(ctx context.Context, req *ns.SendProprietaryPayloadRequest) (*empty.Empty, error) {
  	var mic lorawan.MIC
  	var gwIDs []lorawan.EUI64
  
  	copy(mic[:], req.Mic)
  	for i := range req.GatewayMacs {
  		var id lorawan.EUI64
  		copy(id[:], req.GatewayMacs[i])
  		gwIDs = append(gwIDs, id)
  	}
  
  	err := proprietarydown.Handle(req.MacPayload, mic, gwIDs, req.PolarizationInversion, int(req.Frequency), int(req.Dr))
  	if err != nil {
  		return nil, errToRPCError(err)
  	}
  
  	return &empty.Empty{}, nil
  }
docs: // SendProprietaryPayload send a payload using the 'Proprietary' LoRaWAN message-type.