AReliableOrderedFrameIsNeverRetainedAndIsNotDeliveredToALateJoiner disposed
the first session and then waited on server.ConnectionCount == 0 before
attaching a second one, which timed out under Yggdrasil's ygg-verify
container (dotnet test, cultlib-quic-native-dev image): the retention rule
under test does not depend on the first peer disconnecting, so the fix keeps
both sessions connected concurrently and drops the flaky wait.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
7b7de5b071