if (prevSubscriber != null) {
// we already in the delivery thread, we don't need to equeue a stop request
// just stop it now, since stop is not blocking operation.
// and also it cleans the old state of the active subscriber immediately.
SubscriptionEvent se;
if (deliveryEndPoint.equals(prevSubscriber.deliveryEndPoint)) {
logger.debug("Subscriber {} replaced a duplicated subscriber {} at same delivery point {}.",
va(this, prevSubscriber, deliveryEndPoint));
se = null;
} else {