/**
* Initializes extension driver
*
* @param ObjectManager $objectManager
* @param string $extensionNamespace
* @param object $annotationReader
*/
public function __construct($objectManager, $extensionNamespace, $annotationReader)
{
$this->objectManager = $objectManager;
$this->annotationReader = $annotationReader;
$this->extensionNamespace = $extensionNamespace;
$omDriver = $objectManager->getConfiguration()->getMetadataDriverImpl();
$this->driver = $this->getDriver($omDriver);
}