I'm developing a Flutter app for the web and I need to get the authorization of the user to access his Google Calendar and then create events through Cloud Functions. The problem I'm facing is in using the flutter package google_sign_in and google_sign_in_web, because I could actually use the signIn() method to retrieve the accessToken and the refreshToken, but it is deprecated in favor of renderButton(), as said in the docs.
I'm not so expert in OAuth process and its implementation in Flutter, so I appreciate any advice on it.
(I need the two tokens so I can save them in Firestore)