code: func RequestRXParamSetup(rx1DROffset, rx2Frequency, rx2DR int) storage.MACCommandBlock {
  	return storage.MACCommandBlock{
  		CID: lorawan.RXParamSetupReq,
  		MACCommands: []lorawan.MACCommand{
  			{
  				CID: lorawan.RXParamSetupReq,
  				Payload: &lorawan.RXParamSetupReqPayload{
  					Frequency: uint32(rx2Frequency),
  					DLSettings: lorawan.DLSettings{
  						RX2DataRate: uint8(rx2DR),
  						RX1DROffset: uint8(rx1DROffset),
  					},
  				},
  			},
  		},
  	}
  }
docs: // RequestRXParamSetup modifies the RX1 data-rate offset, RX2 frequency and
  // RX2 data-rate.