Repository: flutter
Issue: AnimatedOpacity + BackdropFilter with ImageFilter.blur lag on the first trigger after building the application
Labels: engine,platform-windows,c: rendering,a: desktop,has reproducible steps,P2,found in release: 2.2,found in release: 2.3,team-windows,triaged-windows

Open gifs in a new tab to make them full sized to see the difference:
![image](https://user-images.githubusercontent.com/63228361/119037998-4e61fe80-b9bb-11eb-941f-c941e1d6477c.png)

Result of the very first hover after building of the application (with BackdropFilter):
![first](https://user-images.githubusercontent.com/63228361/119037716-00e59180-b9bb-11eb-9203-36eb4232e9ec.gif)

Result of the following hovers (with BackdropFilter):
![not_first](https://user-images.githubusercontent.com/63228361/119037776-11960780-b9bb-11eb-877b-1fbecaad3051.gif)

Result of the very first hover (without BackdropFilter):
![first_without_blur](https://user-images.githubusercontent.com/63228361/119037861-296d8b80-b9bb-11eb-884b-2dc7d8c7f189.gif)

The issue happens only on the first hover after building the application; The following animations will work fine and smooth. Hot restart/Hot reload do not reset the issue, you need to stop(close) the application and rebuild it to check the result again. 

Code to repeat the issue:


<details> 
<summary>minimal code sample</summary> 

```dart
import 'dart:ui';

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  bool _showSomething = false;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Material App',
      home: Scaffold(
        backgroundColor: Colors.black,
        body: Stack(
          children: [
            Container(
              width: 2000.0,
              height: 2000.0,
              decoration: BoxDecoration(
                color: Colors.deepPurple,
                border: Border.all(width: 10.0, color: Colors.deepPurple),
              ),
              child: Text(
                  'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.'),
            ),
            Positioned(
              top: 0.0,
              left: 0.0,
              child: MouseRegion(
                onEnter: (_) => setState(() => _showSomething = true),
                onExit: (_) => setState(() => _showSomething = false),
                child: AnimatedOpacity(
                  opacity: _showSomething ? 1.0 : 0.0,
                  duration: Duration(milliseconds: 425),
                  curve: Curves.easeInOutCubic,
                  child: Container(
                    color: Colors.black.withOpacity(0.75),
                    height: 2000.0,
                    width: 2000.0,
                    child: Container(
                      width: 50.0,
                      height: 75.0,
                      child: Text(
                        'Just a text for some reason',
                        style: TextStyle(color: Colors.white),
                      ),
                    ),
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}
``` 

</details>



Flutter version: the latest from the Stable channel. Tested only on Windows.