public function serialize(AbstractMessage $message, array $options = [])
    {
        return [
            'id' => $message->getUuid(),
            'content' => $message->getContent(),
            'meta' => $this->serializeMeta($message),
            'parent' => $this->serializeParent($message),
            'children' => array_map(function (AbstractMessage $child) use ($options) {
                return $this->serialize($child, $options);
            }, $message->getChildren()->toArray()),
        ];
    }