code optimize

lib/assetsChannel.dart

@@ -28,7 +28,7 @@ class _AssestPlatformChannelState extends State<AssestPlatformChannel> {
     }
     setState(() {
       _imageData = imageData;
-      _tttt = 'aaaaa';
+      _tttt = _imageData.runtimeType.toString();
     });
   }