crawl the raw doc, and save it asynchronous.

        :param res: {'url','', 'name': ''}
        :type res: ``dict``
        :return:
        :rtype:

async def crawl_raw(self, res):
        """ crawl the raw doc, and save it asynchronous.

        :param res: {'url','', 'name': ''}
        :type res: ``dict``
        :return:
        :rtype:
        """
        cnt = await self.async_get(res)
        if cnt:
            loop_ = asyncio.get_event_loop()
            await loop_.run_in_executor(None, self.write_hd, res.get('name'), cnt)
            return True
        else:
            return False