CultNetRudpPacketCodec.Decode did checked((int)length), so a datagram declaring
0x80000000 threw OverflowException, which no receive loop catches; the length
is now compared as a long and takes the ordinary malformed-packet drop.
Server mode claimed its endpoint on the first datagram of any type; only a
Connect claims it now. A session that refuses a packet has already recorded
its reliable sequence, so the socket transport and the listener end it: the
session forgets the peer (so the goodbye does not acknowledge the refused
frame), the peer gets a Disconnect, the listener drops the peer and raises
PeerDisconnected, and a server-mode transport forgets its endpoint.
CultNetRudpSession gains ResetPeerState, and the session and the listener
reject an InitialSequence of uint.MaxValue.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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