We can now send messages asynchronously through the MassTransit interface.
We know we can schedule messages with MassTransit/RabbitMQ, but we will not implement it right now. External applications can implement it and schedule the command to be sent to the Portal.
When this is implemented, we could allow message scheduling from the REST interface (returning a 202 Accepted) AND from the MassTransit interface (publishing an event different from MessagesSentEvent).