Method StopDelivery
StopDelivery()
Stops any subclass-owned delivery machinery (e.g. a JetStream pull loop or idle-heartbeat timer) as the first step of a drain, before the UNSUB and the PING/PONG fence. The base implementation is a no-op; subclasses that keep pulling or run a timer that can complete the message channel must override this so drain does not leave that machinery running or let it skip the fence. Called on both the explicit drain and the dispose-drain path; must be idempotent.
protected virtual void StopDelivery()