- TryAttachWorkerClientAndMarkReadyAsync returns SessionAttachOutcome and refuses a
worker client that is already Faulted/Closed; the open discards it and fails OpenFailed.
- MapWorkerEventsAsync calls ObserveWorkerTerminalState when its first readiness check
fails, so a worker that dies between attach and the first pump read faults the session
and the faulted sweep reaps it.
- A caller-cancelled open rolls back, records no fault and rethrows the cancellation
(gRPC Cancelled); an attach refused because the drain closed the session reports
GatewayStopping.
- docs/Sessions.md updated.
Joseph Doherty
a178d68b60