fix navigation error

com.unity.uiwidgets/Runtime/widgets/navigator.cs

             return of(context).pushNamed(routeName, arguments: arguments);
         }
 
-        public static Future<T> pushReplacementNamed<T,TO>(BuildContext context, string routeName,
-            TO result = default , object arguments = null) {
-            return of(context).pushReplacementNamed<T,TO>(routeName, arguments: arguments,result: result);
+        public static Future pushReplacementNamed(BuildContext context, string routeName,
+            object result = default , object arguments = null) {
+            return of(context).pushReplacementNamed(routeName, arguments: arguments,result: result);
-        public static Future<T> popAndPushNamed<T,TO>(BuildContext context, string routeName,
-            TO result = default,
+        public static Future popAndPushNamed(BuildContext context, string routeName,
+            object result = default,
-            return of(context).popAndPushNamed<T,TO>(routeName, result: result, arguments: arguments);
+            return of(context).popAndPushNamed(routeName, result: result, arguments: arguments);
         }
 
         public static Future<T> pushNamedAndRemoveUntil<T>(BuildContext context, string newRouteName,
             return of(context).push<T>(route);
         }
 
-        public static Future<T> pushReplacement<T,TO>(BuildContext context, Route<T> newRoute, TO result = default ) {
-            return of(context).pushReplacement<T,TO>(newRoute, result);
+        public static Future pushReplacement(BuildContext context, Route newRoute, object result = default ) {
+            return of(context).pushReplacement(newRoute, result);
         }
 
        
                 arguments: arguments
             );
 
-            var routeee = widget.onGenerateRoute(settings);
+            var routeee = (Route) widget.onGenerateRoute(settings);
             Route<T> route = routeee as Route<T>;
             if (route == null && !allowNull) {
                 D.assert(() => {
             return push(_routeNamed(routeName, arguments: arguments));
         }
 
-        public Future<T> pushReplacementNamed<T, TO>(
+        public Future pushReplacementNamed(
-            TO result = default,
+            object result = default,
-            return pushReplacement<T, TO>(_routeNamed<T>(routeName, arguments: arguments), result: result);
+            return pushReplacement(_routeNamed(routeName, arguments: arguments), result: result);
-        public Future<T> popAndPushNamed<T, TO>(
+        public Future popAndPushNamed(
-            TO result = default,
+            object result = default,
-            pop<TO>(result);
-            return pushNamed<T>(routeName, arguments: arguments);
+            pop<object>(result);
+            return pushNamed(routeName, arguments: arguments);
         }
 
         public Future<T> pushNamedAndRemoveUntil<T>(
 
         
 
-        public Future<T> pushReplacement<T, TO>(Route<T> newRoute, TO result) {
+        public Future pushReplacement(Route newRoute, object result) {
             D.assert(!_debugLocked);
             D.assert(() => {
                 _debugLocked = true;
                 return true;
             });
             _afterNavigation(newRoute);
-            return newRoute.popped.to<T>();
+            return newRoute.popped.to<object>();
         }
 
         public Future<T> pushAndRemoveUntil<T>(Route<T> newRoute, RoutePredicate predicate) {