'priority' doesn't work

<?php
/**
 * Global Configuration Override
 *
 * You can use this file for overriding configuration values from modules, etc.
 * You would place values in here that are agnostic to the environment and not
 * sensitive to security.
 *
 * @NOTE: In practice, this file will typically be INCLUDED in your source
 * control, so do not include passwords or other sensitive information in this
 * file.
 */

return array(
    'service_manager' => array(
        'abstract_factories' => array(
            'Zend\Log\LoggerAbstractServiceFactory'
        )
    ),
    'log' => array(
        'App\\Log' => array(
            'writers' => array(
                array(
                    'name' => 'stream',
                    'options' => array(
                        'stream' => 'log/app.log',
                        'filters' => array(
                            'priority' => array(
                                'name' => 'priority',
                                'options' => array(
                                    'priority' => Zend\Log\Logger::CRIT
                                )
                            ),
                        ),
                    ),
                ),
            ),
        ),
    ),
);