Pretty sure they don't have "calls that fire". If anything you would have to poll to see whether or not the channel is active at that very moment, and that would become conterproductive quickly.
This is something that should not be overengineered. They are just streaming notifications, this site is not a streaming service nor is it a such service by proxy. This is an art site. A new notification icon for streams? Yes. Being able to browse all active streams? Yes. Implementing a complex array of features that automate infrequent tasks that a streamer would take 30 seconds per day to perform manually? Not worth it.