Joseph Doherty
281e00b300
Remove the per-call allowMultipleSubscribers param from AttachEventSubscriber and derive the mode internally from _eventStreaming.AllowMultipleEventSubscribers — the same source SessionEventDistributor uses for singleSubscriberMode — so the two can never structurally diverge. The maxSubscribers cap param is kept because MaxEventSubscribersPerSession lives in SessionOptions, which the session does not hold directly (only EventOptions flows through SessionEventStreaming). Other nits: - SubscriberCount XML doc clarifies it includes internal subscribers and differs from GatewaySession.ActiveEventSubscriberCount (external/gRPC only). - SingleSubscriberMode_LoneExternalOverflow test: add Assert.Equal(1, observedSet) guard before the value assertion so the test cannot pass vacuously if the handler never fired. - GatewayOptionsValidator.ValidateSessions: add explanatory code comment documenting why !AllowMultipleEventSubscribers && MaxEventSubscribersPerSession > 1 is NOT rejected as a hard error (the default config ships with this combination; the cap is simply unused in single-subscriber mode, not a behavior bug). - GatewaySession.DetachEventSubscriber: add Debug.Assert before the clamp so a genuine double-decrement surfaces in debug builds.