适配flutter sdk的api变动（BuildContext相关）

lib/src/page_load_provider.dart

@@ -17,9 +17,7 @@ class PageLoadProvider extends InheritedWidget {
 
   static String of(BuildContext context) {
     try {
-      return (context.inheritFromWidgetOfExactType(
-          PageLoadProvider) as PageLoadProvider)
-          .env;
+      return context.dependOnInheritedWidgetOfExactType<PageLoadProvider>().env;
     } catch (err) {
       return "pro";
     }

lib/src/page_view_listener_mixin.dart

@@ -103,7 +103,7 @@ mixin PageViewListenerMixin<T extends StatefulWidget> on State<T>, PageTrackerAw
   }
 
   static PageViewListenerWrapperState of(BuildContext context) {
-    return context.ancestorStateOfType(TypeMatcher<PageViewListenerWrapperState>());
+    return context.findAncestorStateOfType<PageViewListenerWrapperState>();
   }
 }
 

lib/src/page_view_wrapper.dart

@@ -34,9 +34,8 @@ class PageViewWrapper extends StatefulWidget {
   static Stream<PageTrackerEvent> of(BuildContext context, int index) {
     try {
       assert(index >= 0);
-      List<Stream<PageTrackerEvent>> broadCaseStreams = (context
-          .ancestorStateOfType(
-          TypeMatcher<PageViewWrapperState>()) as PageViewWrapperState)
+      List<Stream<PageTrackerEvent>> broadCaseStreams = context
+          .findAncestorStateOfType<PageViewWrapperState>()
           .broadCaseStreams;
       assert(index < broadCaseStreams.length);
 

lib/src/tracker_route_observer_provider.dart

@@ -17,8 +17,8 @@ class TrackerRouteObserverProvider extends InheritedWidget {
 
   static TrackerStackObserver<ModalRoute> of(BuildContext context) {
     try {
-      return (context.inheritFromWidgetOfExactType(
-          TrackerRouteObserverProvider) as TrackerRouteObserverProvider)
+      return context
+          .dependOnInheritedWidgetOfExactType<TrackerRouteObserverProvider>()
           .trackerStackObserver;
     } catch (err) {
       return null;