I am relatively new to flutter, but as far as I can tell, the google sign in flutter plugin does not allow you to authenticate with a custom back end using sign in options such as:
.requestIdToken(getString(R.string.server_client_id))

I can login to my google account no issues, but my idToken is always null, which is something we would need to have for our back-end system.

Am I completely misunderstanding how to use this?