How can I setup a Login() verification asyncronously?

Looking at the AGameMode::PreLogin() & ::Login() code, they are syncronous methods that are expected to return immediately and have a string that defines if the login succeeds or fails… Is there a way to do this process asyncronously?

For instance, players connect to a server & pass an authentication or steamID, the server needs to authenticate the user and load the user’s data from a DB/file. Which may take up to a few seconds. And we dont want users to be able to login / create players without authentication.

Whats the proper / suggested way for asyncronous login processes?