Track the contiguous Bun corpus slice at js/third_party/socket.io/socket.io-connection-state-recovery.test.ts (position 4051).
Required parity:
- persist logical Socket.IO sessions across Engine.IO transport replacement;
- recover original socket/private ids, rooms, data attributes, and ordered missed broadcast/room/direct packets;
- preserve packet offsets and emit recovered CONNECT after missed events;
- skip recovery middleware by default while honoring
skipMiddlewares: false; - reject unknown recovery sessions by creating a fresh identity;
- leave adapter persistence hooks untouched when recovery is disabled;
- fix positive-timer ordering so resolved promise chains run before watchdog timeouts;
- keep structured, packet-redacted protocol diagnostics and add permanent regressions.