Second state machine. Models the SFU subscribe leg explicitly:
off ──START──▶ connecting ──CONNECTED──▶ subscribed
│ FAILED │ RENEG
▼ ▼
off renegotiating
│ RENEG_DONE / RENEG_FAILED
▼
subscribed
│ LOST
▼
reconnecting ──CONNECTED──▶ subscribed
│ STOP │ FAILED
▼ ▼
stopping off
│ DONE
▼
off
Renegotiation is its own state so concurrent SSE offers can't race
setRemoteDescription (the bug ae9721e patched imperatively with a
promise queue). A RENEG event during renegotiating parks the SDP on
ctx.pendingOffers; the runtime will drain that queue from an observer
when RENEG_DONE fires. RENEG_FAILED returns to subscribed without
killing the PC — the negotiation attempt is what failed, the channel
itself is still up.
LOST during renegotiating jumps straight to reconnecting (drops the
in-flight reneg cleanly; when the connection comes back the runtime
will re-deliver any still-relevant SDP via fresh RENEGs).
+ 15 new unit tests covering connect, queue, drops, teardown, illegal
transitions. test-fsm now reports 38 passed.
Russell Ballestrini
57013ec9ad