UserIdentity
Each User on Atlas App Services is uniquely identified by their User.id, but this id cannot be used across multiple authentication providers, as they all have their own notation on what defines a user. This class thus represents a users identity towards one single authentication provider.
A single User on App Services can have multiple user identities, one towards each authentication provider, e.g. an example would be an app user that can log in using either a custom email account or a Google account.
The list of all user identities associated with an App Services user can be found through User.identities. It is possible to add more user identities through User.linkCredentials.