/**
* Returns the specified attachment.
*
* @param string $object_id The object id. @since Kolab_Storage 2.1.0
* @param string $attachment_id The attachment id.
*
* @return resource An open stream to the attachment data.
*/
public function getAttachment($object_id, $attachment_id)
{
$this->_init();
return $this->_data_cache->getAttachment($object_id, $attachment_id) ?: parent::getAttachment($object_id, $attachment_id);
}