addThumbnailUrl example

public function addUrls(EntityLoadedEvent $event): void
    {
        /** @var MediaEntity $media */
        foreach ($event->getEntities() as $media) {
            if (!$media->hasFile() || $media->isPrivate()) {
                continue;
            }

            $media->setUrl($this->urlGenerator->getAbsoluteMediaUrl($media));

            foreach ($media->getThumbnails() ?? [] as $thumbnail) {
                $this->addThumbnailUrl($thumbnail, $media);
            }
        }
    }

    public function unserialize(EntityLoadedEvent $event): void
    {
        /** @var MediaEntity $media */
        foreach ($event->getEntities() as $media) {
            if ($media->getMediaTypeRaw()) {
                $media->setMediaType(unserialize($media->getMediaTypeRaw()));
            }