interface EventInterface
{
   public function releaseEvents(): array;
}

trait EventsTrait
{
    private $events = [];

    protected function recordEvent($event): void
    {
        $this->events[] = $event;
    }

    public function releaseEvents(): array
    {
        [$events, $this->events] = [$this->events, []];

        return $events;
    }
}

class Entity implements EventInterface
{
   use EventsTrait;

   public function publish()
   {
       ...
       $this->recordEvent(new EntityPublished($this->id));
   }
}

class Flusher
{
   public function flush(EventInterface ...$entities)
   {
      $this->em->flush();

      foreach($entities as $entity) {
        foreach($entity->releaseEvents() as $event) {
            $this->dispatcher->dispatch($event);
        }
      }
   }
}