off<T>  method 
Navigation.pushReplacement() shortcut .
Pop the current page and pushes a new page to the stack
It has the advantage of not needing context, so you can call from your business logic
You can set a custom transition, define a Tween curve,
and a transition duration.
You can send any type of value to the other route in the arguments.
Just like native routing in Flutter, you can push a route
as a fullscreenDialog,
id is for when you are using nested navigation,
as explained in documentation
If you want the same behavior of ios that pops a route when the user drag,
you can set popGesture to true
If you're using the Bindings api, you must define it here
By default, GetX will prevent you from push a route that you already in,
if you want to push anyway, set preventDuplicates to false
Implementation
Future<T?>? off<T>(
  dynamic page, {
  bool opaque = false,
  Transition? transition,
  Curve? curve,
  bool? popGesture,
  int? id,
  String? routeName,
  dynamic arguments,
  Bindings? binding,
  bool fullscreenDialog = false,
  bool preventDuplicates = true,
  Duration? duration,
  double Function(BuildContext context)? gestureWidth,
}) {
  routeName ??= "/${page.runtimeType.toString()}";
  routeName = _cleanRouteName(routeName);
  if (preventDuplicates && routeName == currentRoute) {
    return null;
  }
  return global(id).currentState?.pushReplacement(GetPageRoute(
      opaque: opaque,
      gestureWidth: gestureWidth,
      page: _resolvePage(page, 'off'),
      binding: binding,
      settings: RouteSettings(
        arguments: arguments,
        name: routeName,
      ),
      routeName: routeName,
      fullscreenDialog: fullscreenDialog,
      popGesture: popGesture ?? defaultPopGesture,
      transition: transition ?? defaultTransition,
      curve: curve ?? defaultTransitionCurve,
      transitionDuration: duration ?? defaultTransitionDuration));
}