How to get Unity Analytics unique user ID?

So far, I understand that Unity Analytics creates a new unique user ID every time my app is downloaded.

https://forum.unity3d.com/threads/how-unity-analytics-recognises-returning-users-and-count-ignore-them-in-dau.377949/#post-2452251

There is a SetUserID function in the Analytics API:

However, how do I get the unique user ID that Unity has generated? There is no corresponding GetUserID function.

@jmahadevan

AnalyticsSessionInfo.userId - UserId is random GUID to track a player and is persisted across game session

On the other hand use for unique install
Social.localUser.id;