:core:data app.hapi.data.sse — the /api/events transport per
docs/api/client-contract/sse.md (reference web/src/hooks/useSSE.ts):
- SseConnection: SseTransport seam (Connected/Event/Failure flow) with the
okhttp-sse implementation on a dedicated client (readTimeout=0, no cache,
own dispatcher), buildEventsUrl, Last-Event-ID header on resume, and an
acceptEncodingIdentity fallback flag for the gzip escape hatch.
- ReconnectPolicy: normative constants + pure backoff schedule (immediate
first retry, 1s..30s exponential, 300s ceiling after 8 attempts, 0..500ms
injected jitter).
- SseEngine: per-key (global / session:<id>) connection loops — handshake
gate on connection-changed{status:connected} with ok/gap resume verdict,
per-key cursors advanced only after the downstream hand-off
(at-least-once), 10s connect deadline, 90s staleness watchdog ticking 10s,
one silent 401 re-auth per cycle costing no backoff attempt, background
retry deferral + 45s foreground stale check; all timing via injected
delay/clock for virtual-time tests.
- SyncEventRouter: 13-type union fan-out to the SyncTargets seam (M2 wires
stores), handshake gap -> requestFullResync, Unknown ignored.
Tests (32): virtual-time engine suite (fake transport + turbine), policy
schedule with seeded jitter, router mapping, and MockWebServer integration
through the real okhttp transport — including proof that gzip SSE frames
surface incrementally (flush-per-event body withheld behind a throttle).
Gzip also verified against a live local hub (Content-Encoding: gzip,
handshake decoded instantly, heartbeat +30.0s mid-stream).
weishu