to that note, it makes more sense to make signal registry as part of the "runner" not the server, but the server is the target of the runner commands

broker shouldn't be considered a first class object in the server as it is only part of the zeromq server to make the server run, not sure where that is a concern

I don't see a reason to remove evented or socket server/client, it would stop function of the most common connectivity interfaces (raw tcp sockets) without any benefit, are there any?