prestashop-module/retailcrm/lib/api/pipeline/RetailcrmMiddlewareInterface.php

<?php

interface RetailcrmMiddlewareInterface
{
    /**
     * @param RetailcrmApiRequest $request
     * @param callable|null $next
     * @return RetailcrmApiResponse
     */
    public function __invoke(RetailcrmApiRequest $request, callable $next = null);
}