namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\Notifier\Notification\Notification;

class SandboxController extends AbstractController
{
    /**
     * @Route("/onboarding", name="onboarding")
     */
     public function __invoke(): Response
     {
       $notification = new Notification('Welcome Sma <3', ['chat/slack']);
       $this->notify($notification);
       // stuff
     }
}