async def flush(self, request: BernardRequest):
        """
        If there's a AnswerCallbackQuery scheduled for reply, place the call
        before actually flushing the buffer.
        """

        if self._acq and 'callback_query' in self._update:
            try:
                cbq_id = self._update['callback_query']['id']
            except KeyError:
                pass
            else:
                await self.platform.call(
                    'answerCallbackQuery',
                    **(await self._acq.serialize(cbq_id))
                )

        return await super(TelegramResponder, self).flush(request)
If there's a AnswerCallbackQuery scheduled for reply, place the call
        before actually flushing the buffer.