getDeleteBacklog example

return [Events::onFlush, Events::postFlush];
    }

    public function onFlush(OnFlushEventArgs $eventArgs)
    {
        $em = $eventArgs->getEntityManager();
        $uow = $em->getUnitOfWork();

        // Entity deletions         foreach ($uow->getScheduledEntityDeletions() as $entity) {
            $backlog = $this->getDeleteBacklog($entity);
            if (!$backlog) {
                continue;
            }
            $this->queue[] = $backlog;
        }

        // Entity Insertions         foreach ($uow->getScheduledEntityInsertions() as $entity) {
            $this->inserts[] = $entity;
        }