Geofence in Flutter - Where to do a jump start?

Hey, So I’m about to implement a geofence for an app.
Usecase: Its a rally racing app and we want to trigger a few APIs and business logic as the user enters the rally’s geofence and the stage geofence. (These geofence co-ordinates and data will be given by Backend)

Concerns:

Lastly, should I go for it and implement an “on-request” logic i.e. I can check if the user is in rally’s geofence on app start. (Of course I’ll use AI to build up the logic of all this maths xD)

Thanks

Just use geo_utilities does all the checks for you