The "client-less" approach would be particularly nice for use with IoT devices which don't have enough CPU/memory to run a beefy pub/sub client (which is typica

The "client-less" approach would be particularly nice for use with IoT devices which don't have enough CPU/memory to run a beefy pub/sub client (which is typical of other solutions). So that's nice. Is there a way to perform access control on the backend? E.g. Is there a way to prevent a specific user from subscribing to a specific channel (if they are not allowed)? Or is this specifically designed to deal only with public channels (that anyone can publish/subscribe to)?