Send a batch of messages

        :param str topic: a kafka topic
        :param ksr.transport.Message kmsgs: Messages to serialize
        :param int timeout: Timeout in seconds
        :return: Execution result
        :rtype: kser.result.Result

def bulk_send(self, topic, kmsgs, timeout=60):
        """ Send a batch of messages

        :param str topic: a kafka topic
        :param ksr.transport.Message kmsgs: Messages to serialize
        :param int timeout: Timeout in seconds
        :return: Execution result
        :rtype: kser.result.Result
        """

        try:
            for kmsg in kmsgs:
                self.client.send(
                    topic, self._onmessage(kmsg).dumps().encode("UTF-8")
                )
            self.client.flush(timeout=timeout)
            return Result(stdout="{} message(s) sent".format(len(kmsgs)))

        except Exception as exc:
            return Result.from_exception(exc)