I'm still a beginner, but I was wondering why :pg is used to get all the PIDs of the PGServer processes in the cluster and send them messages (e.g., {:broadcast_to_local, topic, message}). Why not use something like Enum.each(Node.list(), fn node -> Hermes.broadcast_local(topic, message) end) instead? I'm sure there's a good reason, I'm just trying to understand how it all works.