Engine.IO v3 frames over WebSocket prepend the packet-type byte (0x04
for Message) to BINARY frames, the binary analog of the leading digit
on text frames. The real client honors this and our session was
treating the entire binary frame as the Socket.IO attachment payload —
the msgpack decoder saw 0x04 as a positive fixint and failed
deserialization on every inbound msg event.
Symmetric fix: strip 0x04 from inbound binary frames in
BattleSession.RunAsync, prepend 0x04 to outbound binary frames in
EncodeAndSendAsync. RawSocketIoTestClient gets the same on both
directions so the integration test still exercises the same wire
shape as a real client.
Caught during v1 smoke walkthrough, after the WS upgrade started
succeeding (101 Switching Protocols).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
- Wrap HandleMsgEventAsync / HandleAliveEventAsync bodies in try/catch(Exception)
logging at Error, eliminating async-void unobserved-exception crash risk (Issue 1).
- Replace deterministic seq-based key generator with RandomNumberGenerator.GetInt32
so each EncodeAndSendAsync call uses a fresh random key (Issue 2).
- Add `when Phase == …` guards to InitNetwork / Loaded / Swap cases in
ComputeResponses; add default arm that logs+drops out-of-order URIs (Issue 3).
- Widen SendSioAckAsync arg from int to long; drop (int) cast at call site;
boundary cast to int is now checked() for defensive overflow detection (Issue 4).
- Update RunAsync doc comment (was stale Task-13 placeholder) (Issue 5).
- Add Kill and out-of-order-Swap-before-Loaded tests (Issue 6).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
