I found a problem through debugging. When I debug it very slowly From pub/index.php to my custom api method.I want to fix and make faster,but I dont’t know how to start.
vendor/magento/framework/App/Http.php (116 rows dispatch) -> vendor/magento/module-webapi/Controller/Rest.php
->vendor/magento/module-webapi/Controller/Rest/SynchronousRequestProcessor.php