get_dimensions() would be called exactly twice; once at the very start, to get the 'id', and a second time to get the injected bot_config value.

Eventually we would want to get rid of this "injected upon handshake bot_config", but that's more complicated. See issue 786733.

Then the dimensions would be stored on the server and not sent anymore. This will reduce the chatter on the RPCs and permits better more accurate precalculation of capacity for queues.

When a bot hook would want to update the dimensions, this would require a way for the hook to signal bot_main to restart itself. This could probably be an exception (?)