main function

void main()

"Set the preferred orientation of the app to landscape, then run the app."

The first line of the function is a call to WidgetsFlutterBinding.ensureInitialized(). This is a function that is called automatically when the app starts, but it's a good idea to call it explicitly in main() to make sure that the app is initialized before we try to set the preferred orientation

Implementation

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  SystemChrome.setEnabledSystemUIMode(
    SystemUiMode.manual,
    overlays: <SystemUiOverlay>[
      SystemUiOverlay.bottom, //This line is used for showing the bottom bar
    ],
  );
  SystemChrome.setPreferredOrientations(<DeviceOrientation>[
    DeviceOrientation.landscapeLeft,
    DeviceOrientation.landscapeRight,
  ]).then((void value) => runApp(const MyApp()));
}