Message Function
All messages have a message envelope with a MessageFunction. Message Function can be three different options:
| Message Function | Description |
| Original | The first message of each type will be Original. |
| Replace | Some message types can be sent several times and a change will be sent as a replace to update information that has been sent before. |
| Cancellation | If a previous message should be cancelled and not replaced it is sent as a Cancellation. |