There's a lot of complexity with having ring buffers and so forth, and they are a source of some confusion and bugs. We would benefit greatly from this being significantly simpler.

For use cases where a small ring buffer greater than 1 is appropriate, it seems like a sufficient solution is just to store all the relevant information in every message and send that.

For use cases where large amounts of information should be cached, it seems like a solution is to have the plugin do the caching and await a request.

We should see whether any plugins are making use of the ChannelBuffers control channel. If none are, that would be a good signal that we can just remove this. If some are, we should investigate what the use cases are.