No longer use socket as key in maps, instead, use the session id. Only use the session id in the sender thread, "resolve" it to the socket only in the moment when it is needed. Outstanding requests will be detected to have an invalid session id then.
Also, as side effect, fixed an issue with two callback classes which were named the same and caused unexpected behavior.
AvatarManager is now thread safe.
Default and cached avatars are handled in different lists to prevent deleting the default avatars when clearing the cache.
There is a lobby thread for the server, and each game has its own game processing thread and a sender thread. Connections can be accepted from different sources, i.e. TCP/SCTP over IPv4, IPv6, all those work well in parallel.
lotodore