magento-test/app/code/Magento/WebapiAsync/etc/webapi_async.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<services xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_WebapiAsync:etc/webapi_async.xsd">
    <route url="async/V1/products" method="POST" alias="asyncProducts" />
</services>