code: func (step *CallFlowTransferStep) UnmarshalJSON(data []byte) error {
  	var raw jsonCallFlowTransferStep
  	if err := json.Unmarshal(data, &raw); err != nil {
  		return err
  	}
  	*step = CallFlowTransferStep{
  		CallFlowStepBase: raw.CallFlowStepBase,
  		Destination:      raw.Options.Destination,
  		Record:           raw.Options.Record,
  	}
  	return nil
  }
docs: // UnmarshalJSON implements the json.Unmarshaler interface.