Symfony 4 - KnpMenuBundle - menu with event

Menu.php

<?php
// src/Menu/Menu.php

namespace App\Menu;

use App\Event\Menu\Topbar\UserMenuEvent;
use Knp\Menu\FactoryInterface;
use Knp\Menu\ItemInterface;
use Symfony\Component\EventDispatcher\EventDispatcherInterface;
use Symfony\Component\HttpFoundation\RequestStack;

class Menu
{

    /**
     * @var EventDispatcherInterface
     */
    private $dispatcher;

    /**
     * @var FactoryInterface
     */
    private $factory;

    public function __construct(FactoryInterface $factory, EventDispatcherInterface $dispatcher)
    {
        $this->dispatcher = $dispatcher;
        $this->factory = $factory;
    }

    public function userTopbar(RequestStack $request): ItemInterface
    {
        $menu = $this->factory->createItem('root');

        $this->dispatcher->dispatch(
            UserMenuEvent::EVENT,
            new UserMenuEvent($this->factory, $menu, $request)
        );

        return $menu;
    }

}

services.yaml

// config/services.yaml

services:
    app.menu_builder:
        class: App\Menu\Menu

    app.menu.usertopbar:
        class: Knp\Menu\MenuItem
        factory: ['@app.menu_builder', 'userTopbar']
        tags:
            - { name: knp_menu.menu, alias: userTopbar }

topbar.html.twig

{# templates/topbar.htm.twig #}

{{ knp_menu_render('userTopbar') }}

UserMenuEvent.php

<?php
// src/Event/Menu/Topbar.php

namespace App\Event\Menu\Topbar;

use Knp\Menu\FactoryInterface;
use Knp\Menu\ItemInterface;
use Symfony\Component\EventDispatcher\Event;
use Symfony\Component\HttpFoundation\RequestStack;

class UserMenuEvent extends Event
{
    public const EVENT = 'app.menu.topbar.user';

    /**
     * @var FactoryInterface
     */
    private $factory;

    /**
     * @var ItemInterface
     */
    private $item;

    /**
     * @var RequestStack
     */
    private $request;

    public function __construct(FactoryInterface $factory, ItemInterface $item, RequestStack $request)
    {
        $this->factory = $factory;
        $this->item = $item;
        $this->request = $request;
    }

    /**
     * @return FactoryInterface
     */
    public function getFactory(): FactoryInterface
    {
        return $this->factory;
    }

    /**
     * @return ItemInterface
     */
    public function getItem(): ItemInterface
    {
        return $this->item;
    }

    /**
     * @return RequestStack
     */
    public function getRequest(): RequestStack
    {
        return $this->request;
    }

}

UserMenuSubscriber.php

<?php
// src/Subscriber/UserMenuSubscriber.php

namespace App\Subscriber;

use App\Entity\User;
use App\Event\Menu\Topbar\UserMenuEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface;
use Symfony\Component\Translation\TranslatorInterface;

class UserMenuSubscriber implements EventSubscriberInterface
{

    /**
     * @var TokenStorageInterface
     */
    private $tokenStorage;

    /**
     * @var TranslatorInterface
     */
    private $translator;

    public function __construct(TokenStorageInterface $tokenStorage, TranslatorInterface $translator)
    {
        $this->tokenStorage = $tokenStorage;
        $this->translator = $translator;
    }

    public function onUserMenuConfigure(UserMenuEvent $event)
    {
        $menu = $event->getItem();
        /** @var User $user */
        $user = $this->tokenStorage->getToken()->getUser();

        $dropdown = $menu->addChild(
            $this->translator->trans('Hello %username%', ['%username%' => $user->getUsername()], 'usermenu'),
            ['dropdown' => true]
        );

        $dropdown->addChild(
            $this->translator->trans('Profile', [], 'usermenu'),
            ['route' => 'profile_index']
        );
    }

    public static function getSubscribedEvents(): array
    {
        return [
            UserMenuEvent::EVENT => 'onUserMenuConfigure',
        ];
    }
}