* Chat Server Actor is a System Service that runs in the same thread as the HttpServer/WS Listener.
* The [actix-broker](https://github.com/Chris-Ricketts/actix-broker) crate is used to facilitate the sending of some messages between the Chat Session and Server Actors where the session does not require a response.
* The Client is not required to send Ping messages. The Chat Server Actor auto-clears dead sessions.
* Could the Chat Server Actor be simultaneously a System Service (accessible to the Chat Session via the System Registry) and also run in a separate thread?