Joseph Doherty
ec9f26400a
- Open path: the attach gate now waits on CancellationToken.None and the manager discards (kills + disposes) the late worker client on ANY exception out of the attach step, including the caller's own cancellation (checked first, so an abandoned open never yields a session). Previously an OperationCanceledException from the gate wait escaped before the discard and orphaned the x86 worker. The gate Release is guarded against ObjectDisposedException. - Unattached grace: AttachInternalEventSubscriber sets a separate latch so the gateway's own alarm-monitor session (internal subscriber only) is never reaped; the idle clock starts at Ready (MarkReady stamps _readyAtUtc) instead of at open, so a slow worker start does not eat the window. - KillWorkerAsync / CloseSessionCoreAsync: an ObjectDisposedException from the close gate on a session that is no longer registered means a concurrent close already removed, accounted and disposed it; both now return AlreadyClosed with no fault, no second gauge decrement and no sweep failure. The general kill catch only decrements the gauge when the session is still registered. The sweep no longer counts AlreadyClosed results among the sessions it closed.