EventDispatcher Component
  =========================
  
  The Symfony2 EventDispatcher component implements the Mediator pattern in a
  simple and effective way to make your projects truly extensible.
  
      use Symfony\Component\EventDispatcher\EventDispatcher;
      use Symfony\Component\EventDispatcher\Event;
  
      $dispatcher = new EventDispatcher();
  
      $dispatcher->addListener('event_name', function (Event $event) {
          // ...
      });
  
      $dispatcher->dispatch('event_name');
  
  Resources
  ---------
  
  You can run the unit tests with the following command:
  
      $ cd path/to/Symfony/Component/EventDispatcher/
      $ composer.phar install
      $ phpunit