Now that authentication and user to process linking is coming along, we can now have rooms created on different servers and seamlessly join clients to them.
This is good as when we scale up servers, players can be located on any random one. So if they were wanting to play together we need to be able to get them in the same room on the same server.
This will also allow us to seamlessly shut down servers in the future, when scaling down or when restarting to apply updates. Usually a player will stay on the same server when changing rooms, but if that server is due to shut down, we can take that opportunity to send them elsewhere. This will slowly empty the server until it's safe to shutdown.
When changing rooms, if it's on the same process, we can just move the user across, and send down the new data. And if it's on a different server, we can now send back a message to the client telling them which server to connect to with a redirect auth token. The token is processed on the new server, and the user is moved to the room, and the client is finally sent the data.
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