Users tracking into custom visual

Hi guys! I'm developing custom visuals for our company. How can I track user count(Reviewer and Editors) into our custom visuals to differentiate license levels by the number of users as it is already done in many companies (ZebraBI, XViz, etc...)? 

I've found the authenticationService here https://docs.microsoft.com/en-us/power-bi/developer/visuals/visual-api.
But there is not very reach documentation

• authenticationService, generates a service to help with user authentication
  
  Please let me know if this service can help me to differentiate license levels by the number of users?
  Thank you in advance
  Regards, 
  Alex.