StupidController.php

<?php

namespace AcmeBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Site\RsrSecurityBundle\Service\RsrNwlSystem;

class ServiceController extends Controller
{
    public function serviceRelatedAction()
    {
        /** @type RsrNwlSystem $service */
        // $service - инстанс заданного в services.yml класса
        $service = $this->get('rsr.sendurl');
        $response = $service->sendRequest();
        // ...
    }
}