fix: build and unit test name

packages/video_player/video_player/test/video_player_test.dart

@@ -1050,7 +1050,7 @@ void main() {
         await tester.runAsync(controller.dispose);
       });
 
-      testWidgets('buffering status', (WidgetTester tester) async {
+      testWidgets('duration update', (WidgetTester tester) async {
         final VideoPlayerController controller =
             VideoPlayerController.networkUrl(_localhostUri);
 

packages/video_player/video_player_platform_interface/lib/video_player_platform_interface.dart

@@ -349,6 +349,9 @@ enum VideoEventType {
   /// The video stopped to buffer.
   bufferingEnd,
 
+  /// The video duration has updated. 
+  durationUpdate,
+
   /// The playback state of the video has changed.
   ///
   /// This event is fired when the video starts or pauses due to user actions or