public function __construct(ClientInterface $databaseDriver, $cacheDirectory = null, EventManager $eventManager = null)
{
$this->annotationDriver = new AnnotationDriver($cacheDirectory);
$this->eventManager = $eventManager ?: new EventManager();
$this->uow = new UnitOfWork($this);
$this->databaseDriver = $databaseDriver;
$this->metadataFactory = new GraphEntityMetadataFactory($this->annotationDriver->getReader());
}