docs: 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