Neos\Flow\Persistence\AbstractPersistenceManager::clearState PHP Method

    public function clearState()
    {
        $this->newObjects = [];
    }

 /**
  * Clears the in-memory state of the persistence.
  *
  * Managed instances become detached, any fetches will
  * return data directly from the persistence "backend".
  *
  * @return void
  */
 public function clearState()
 {
     parent::clearState();
     $this->entityManager->clear();
 }