Can't get working Flutter Crashlytics

[KengooMurzik]

Hi

I added all required references in build.gradle files, pubspec,yaml and app's code, but I can't get working flutter crashlytics.
Nothing happens after I do this:

Crashlytics.instance.enableInDevMode = true;
Crashlytics.instance.log('YOUR LOG COMES HERE');
Crashlytics.instance.log('YOUR LOG COMES HERE');
  FlutterError.onError = (FlutterErrorDetails details) {
    Crashlytics.instance.log('Error!!!!!!!!!!!!!!!!');
  };

and after error is thrown.

Could you help me to make it working please?