protected function toArray(TransUnitInterface $transUnit)
    {
        $data = array(
            'id'           => $transUnit->getId(),
            'domain'       => $transUnit->getDomain(),
            'key'          => $transUnit->getKey(),
            'translations' => array(),
        );

        foreach ($transUnit->getTranslations() as $translation) {
            $data['translations'][] = array(
                'locale'  => $translation->getLocale(),
                'content' => $translation->getContent(),
            );
        }

        return $data;
    }