Replace Task.Delay(100) subscriber-attachment races with WaitForSubscriberCountAsync,
a polling gate on GatewaySession.ActiveEventSubscriberCount so Advise and event fan-out
cannot proceed until all subscribers are confirmed registered.
Fix WaitForMessageCountAsync to honor a single CancellationTokenSource deadline across
the poll loop rather than resetting the timeout on each intermediate wakeup.
Add ordering comment in the cancellation test explaining why stream1Task must be awaited
before AllowNextEvent to guarantee sub1 is unregistered before the 2nd event is fanned.
Assert capException.Status.Detail contains "maximum" in the cap test to distinguish
EventSubscriberLimitReached (AllowMultiple=true cap) from EventSubscriberAlreadyActive
(single-subscriber rejection) — both map to ResourceExhausted.
Extract shared ConfigureCommandReply helper and move FakeWorkerProcess to TestSupport/
so both fake-worker test classes reference one definition.
Adds GatewayEndToEndMultiSubscriberTests covering three scenarios
through the real gRPC StreamEvents path with AllowMultipleEventSubscribers=true:
- Fan-out: two concurrent StreamEvents RPCs both receive every event the fake
worker emits, in the same order (WorkerSequence matches, values indexed).
- Independent cancellation: cancelling one subscriber's stream leaves the other
receiving subsequent events; the session stays usable.
- Cap enforcement: with MaxEventSubscribersPerSession=2 a third concurrent
StreamEvents is rejected with gRPC ResourceExhausted while the first two
keep streaming.
Extends RecordingServerStreamWriter<T> with WaitForMessageCountAsync to
allow deterministic bounded-timeout awaits for an N-message count without
fixed sleeps.
Joseph Doherty