Is there a way to get a Users Username (not Display Name) with Snapchats Login Kit?

I am developpong a new app for which it could be helpful to get a Users Snapchat Username from the Login Process provided by Snapchats Login Kit. Getting the Display name and an external ID seems to be possible, but I am interested in finding a way to get the real Username (which is also used as an identifier to add another user as a friend). It would be interesting to hear if somebody was able to do that.