I'm developing a Xamarin.Forms app, and using AuthenticationManager.Current.GetCredentialAsync() to challenge the user for credentials to our Portal. We can then use ArcGISPortal.CreateAsync(uri, cred) to get the Portal instance and access to user content and data. My question is: Is there a way to cache the Credentials object or something similar? I don't want to have to prompt the user for credentials every time they open the app, when things like tokens can last for days. I've looked at locally storing the token itself, but that doesn't help get me an authenticated ArcGISPortal object.