[📚] documentation for enabling debug mode in firebase_analytics

[stephane-archer]

the documentation doesn't explain clearly how to Enable debug mode when using Flutter.
MacOS is not even mentioned.
https://support.google.com/analytics/answer/7201382

[russellwheatley]

@stephane-archer - "iOS+" essentially means macOS as well:

@kevinthecheung - is there any way to update this page for debugging Flutter apps? We don't have access from FlutterFire repo.

Essentially, web and android require same setup and can be run via Flutter CLI (i.e. flutter run). But iOS/macOS also require the same setup, but are different in the sense that you have to run the app from Xcode (i.e. it won't work with flutter run).