In this example,
SingIt package is called from the IDT app with the launchSingIt method, which accepts the config SingItPackage and BuildContext to navigate to the starting screen of SingIt. Of course the starting screen can vary based on UserInfo from SingItPackage config.
Hard requirements from IDT's side is that the contract between our app and the package is according to this example's SingItPackage. The actual implementation such as state management is up to the SingIt team.