McNeel - Google Analytics Hits

So I have the attached code working... It successfully registers a "hit" with google analytics when a user runs a solution that includes a plugin a wrote. 

My next step is to figure out something I can use as a client ID or user ID.

https://developers.google.com/analytics/devguides/collection/protoc...

This can be any string or a UUID, with a few conditions (in order of most important to least):

It cannot be personally identifiable information or any form of sensitive information

It would be the same for any given user, even if they close and then reopen rhino/ grasshopper (so system based, not session-based or random)

It would be different for different users

I just came across this function in the docs for V6 RhinoCommon:

http://developer.rhino3d.com/api/RhinoCommonWin/html/T_Rhino_Runtim...

It seems like the guys at McNeel are making this super easy! In the meantime, while working with Rhino 5, can anyone guess as to how that function picks its user id/ client id?

Thanks!