Game sometimes hangs when client attempts to start a match

[randomPoison]

After implementing support for discarding tiles was added in 1a1d760, the game has started to hang when entering a match. This doesn't happen every time, but it does seem to happen a majority of the time.

If we exit play mode while the client is in this stuck state, we get an exception indicating that the client is still awaiting the match start response from the server:

TaskCanceledException: A task was canceled.
<...>
WebSocket+<RecvStringAsync>d__2.MoveNext () (at Packages/com.synapse-games.websockets/Runtime/WebSocket.cs:25)
<...>
Synapse.Mahjong.Match.MatchController+<<Init>g__RequestStartMatch|15_0>d.MoveNext () (at Assets/Scripts/Match/MatchController.cs:107)
<...>

Which points back to the await in this code:

// Request that the server start a match.
var request = _client.CreateStartMatchRequest();
_socket.SendString(request);
var responseJson = await _socket.RecvStringAsync(cancellation);

There's very little logging on the server side currently, so it's difficult to tell what's going on, but it seems likely that the server is dead-locking somewhere in the handling logic for the start match response.

[randomPoison]

A good first step would be to get logging in place via the tracing crate. This will allow us to narrow down the source of the problem.

[randomPoison]

Note that the client will also sometimes get stuck at the very beginning during startup, too. This is more rare, though.

[randomPoison]

After restarting my client a few times this is no longer happening with as much consistency. I've added server logging so it should be much easier to debug this issue when it happens again, though.