How to keep user login

[emaborsa]

Hi all,
I have implemented the library into my Flutter Android app, the user can login, where the userId is stored in the SharedPreferences.
If I put the app in background, once the app is reopened few seconds later, everything is working fine.
If I close the app by hitting the back button, even if I reopen it after just a second, the AzureB2C.getSubjects() returns an empty list so I cannot trigger AzureB2C.policyTriggerSilently(...) with the previously saved userId.

Is there a way to let's say store the session in order to keep the user loggin in?