I have been looking into this myself but my python skills are just above 0 - So here is my research so far…
The unofficial work on Netgear Arlo undocumented API on this site: RG Blog has a section around three quarters of the page down titled “EVENT PUBLICATION AND SUBSCRIPTION” - This lists two API calls that can be performed on the Netgear Arlo API as EventStreams.
I have searched the PyArlo project on GitHub and it would appear that this API call is exposed in the Base Station object.
Given that HomeAssistant now has an Asyncronous core that can be used, it would make sense to refactor the codebase away from the old polling and blocking methods across to the new Async framework with the EventStreams returned from PyArlo.
This would give added benefits too such as being able to use ‘Motion’ event feeds from the Arlo cameras and would also be less of a burden on resource - Data would be returned as and when it changes so, a full refresh would only be required on initialisation.