docs: def _handle_task(self):
          """Pass request info to the async framework."""
          headers = self.request.headers
  
          message = None
          try:
              status_code, output = process_async_task(
                  headers, self.request.body)
          except AbortAndRestart as restart:
              # Async retry status code
              status_code = 549
              message = 'Retry Async Task'
              output = str(restart)
  
          self.response.set_status(status_code, message)
          self.response.out.write(output)