public function toArray()
    {
        $content = [
            'id' => $this->content->id,
            '_content' => $this->content->toArray(),
            '_revision' => $this->revision->toArray(),
        ];

        foreach ($this->data as $field => $data) {
            $content[$field] = $data->toArray();
        }

        return $content;
    }