Controller.php

<?php
class Controller {
  public function handle(Request $request) {
    $event = new TryToRegisterUserEvent($request->get('email'));
    
    $this->dispatcher->dispatch($event);
  }
}

TryToRegisterUserEventHandler.php

<?php
class TryToRegisterUserEventHandler {
  public function handle(TryToRegisterUserEvent $event) {
    $user = $this->userRegistrationDomainService->register($event->getEmail());

    $userRegistered = new UserRegisteredEvent($user);
    $this->dispatcher->dispatch($userRegistered);
  }
}

UserRegisteredEventHandler.php

<?php
class UserRegisteredEventHandler {
  public function handle(UserRegisteredEvent $event) {
    $user = $event->getUser();
    // do something...
  }
}