public List<Object> getHelperQueueList() {
    getInitializationLock().readLock().lock();
    try {
      if (getPartitionedRegion().isDestroyed()) {
        throw new BucketRegionQueueUnavailableException();
      }
      return eventSeqNumDeque.stream()
          .map(this::optimalGet)
          .filter(o -> o instanceof GatewayQueueEvent)
          .collect(Collectors.toList());

    } finally {
      getInitializationLock().readLock().unlock();
    }
  }
Overriding this method from AbstractBucketRegionQueue in order to remove the event from
eventSeqNumQueue if EntryNotFoundException is encountered during basicDestroy. This change is
done during selective merge from r41425 from gemfire701X_maint.
geode-core/src/main/java/org/apache/geode/internal/cache/BucketRegionQueue.java