KCP max connections reached does not work as intended.

[JesusLuvsYooh]

Describe the bug
KCP Client does not 'disconnect' upon attempting to join a full server.
It gets stuck on connecting UI until timeout is reached (10,000ms).
Works as expected with Telepathy.

[IMPORTANT] How can we reproduce the issue, step by step:
Have 2 editors open, tanks example, set max connections on NetworkManager to 1.
Set KCPTransport logs to true.
StartHost, then StartClient on other editor.

Expected behavior
Client gets some sort of callback straight away, to say failed to connect, rather than waiting for 10s timeout to kick in.

Desktop (please complete the following information):
Mac, Unity 2021, Any of latest Mirrors.

Additional context Screenshots
Further info/discussions in Discord.

Notes from Ninja:
Hard to say. Should be client. I can't tell if client received the disconnect message or not, and just wait for handshake.
Or is it server disconnects too soon and does not even send the handshake (if on same batch or something).
I haven't looked at it close up. if server does (receive handshake, send handshake, add connection, on connect, disconnect, as per the logs), and the disconnect destroys the connection immediately while handshake messages are queued to end of frame, then might be an issue? pure guess at this stage, didn't even look at code.

[miwarnec]

update 2024:

[miwarnec]

SendDisconnect is called, but it doesn't go through.
forcing with flush+update+sleep does work:

just need a better solution

[miwarnec]

fix is on kcp repo.
it now detects the disconnect immediately.
still shows a few warnings, but that's for next few days.