Using Rc in Agent does not allow to do tokio::spawn
For some tasks I'd like to do tokio:spawn for my Agent, but it contains Rc which are not Send. This Rc are not really needed, because they contain a very small amount of data (lang: Vec, and default_nick: String). Simple change Rc to Arc (or even removing Rc and make a simple clone) fixes the issue. Would it be possible to remove Rc, please? I can send a PR if needed.