fix

README.md

             protected override Widget createWidget() {
                 return new WidgetsApp(
                     home: new ExampleApp(),
-                    pageRouteBuilder: this.pageRouteBuilder);
-            }
-    
-            protected virtual PageRouteFactory pageRouteBuilder {
-                get {
-                    return (RouteSettings settings, WidgetBuilder builder) =>
+                    pageRouteBuilder: (RouteSettings settings, WidgetBuilder builder) =>
-                        );
-                }
+                        )
+                );
             }
     
             class ExampleApp : StatefulWidget {