- split swarm worker into two modules
- split socket worker into two modules
- keep track of which offers peers have sent and only allow matching
answers
- always clean up after closing connection
- use channel for telling connections to close
- move some logic into new ConnectionRunner struct
- use slotmap for connection reference storage
- fix double counting of error responses
- actually close connections that take too long to send responses to
- remove announced_info_hashes entry on AnnounceEvent::Stopped
