magento-test/app/code/Magento/MediaGallerySynchronization/etc/communication.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:Communication/etc/communication.xsd">
    <topic name="media.gallery.synchronization" is_synchronous="false" request="string[]">
        <handler name="media.gallery.synchronization.handler"
                 type="Magento\MediaGallerySynchronization\Model\Consume" method="execute"/>
    </topic>
</config>