Update extension triggered by timer

I am working on an extension (for USD Composer) and I would like to update the extension based on time.

A good demonstration of the functionality I am looking for would be to make a digital clock extension that ticks away while the extension is open.

I have tried looking through the different carb event types, but haven’t identified any events that happen consistently/dependably enough to be used to trigger my update.

Any help would be greatly appreciated.