The interface is designed so that a websocket client
can connect at any time and it will recieve all information
as soon as the current round finishes.
We send a CurrentRoundUpdate during the round, when the cards change.
Even if the cards don't change, this will be updated after ~2 seconds.
When the round is finished, we send a RoundHistory.
After a finished round we the last 100 rounds that we have cached.
This is so that any frontend can catch up with the recent history,
without requiring a database.
In the future this might not be needed if the consumer of this API
has its own database.