'Put `message` onto `queue`.
This simply writes a key to the Etcd store
Arguments:
queue (str): The name of the queue.
payload (dict): Message data which will be dumped to etcd.'

def _put(self, queue, payload, **_):

    with self._queue_lock(queue):
        key = self._key_prefix(queue)
        if (not self.client.write(key=key, value=dumps(payload), append=True)):
            raise ChannelError(u'Cannot    add    key    {0!r}    to    etcd'.format(key))
