main.dart

...
class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MultiBlocProvider(
        providers: [
          BlocProvider(
            create: (context) => UsuarioCubit(),
          ),
        ],
        child: MyHomePage(title: 'Cubit Provider'),
      ),
    );
  }
}
...