Async events

AsyncTrait.php

<?php

use Symfony\Component\EventDispatcher\EventDispatcherInterface;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\EventDispatcher\Event;

trait AsyncDispatcherTrait
{
    /** @var EventDispatcherInterface */
    protected $dispatcher;

    /** @var null|Event[] */
    protected $pendingEvents = null;

    public function setDispatcher(EventDispatcherInterface $dispatcher)
    {
        $this->dispatcher = $dispatcher;
    }

    public function notifyAsync()
    {
        $events = $this->pendingEvents;
        $this->pendingEvents = [];
        foreach ($events as $type => $event) {
            $this->dispatcher->dispatch($type, $event);
        }
    }

    protected function async($type, Event $event)
    {
        if (null === $this->pendingEvents) {
            $this->pendingEvents = [];
            $this->dispatcher->addListener(KernelEvents::TERMINATE, array($this, 'notifyAsync'));
        }

        $this->pendingEvents[$type][] = $event;
    }
}