fix(player): 修复拖动进度条时加载态闪烁

lib/pages/player/widgets/home_feed_overlay.dart

@@ -1,5 +1,7 @@
 // Author: fruit.com.cn
 
+import 'dart:async';
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:video_player/video_player.dart';