PHP 7.3 reaches end of support in December 2021 and Adobe Commerce 2.3.x reaches end of support in April 2022. You may want to consider planning your upgrade now to Adobe Commerce 2.4.x and PHP 7.4.x to help maintain PCI compliance.
WebapiAsync
WebapiAsync Extends Webapi extension and provide functional to process asynchronous requests. It handle asynchronous requests, schedule, publish and consum bulk operations from queue.