This library service will be invoked when the user opens the client app and is going to perform an action that requires identification. This is because it is an action of personal data or performing a purchase action, identity verification, etc.
At the desired point, the client will invoke the library to perform the relevant identification actions, once the process is completed by the library, it returns the data of the identified user.
The process can be cancelled for various reasons, in which case the corresponding error code is returned to show through the UI of the client app the reason why it has not been possible to complete the identification.