记得好久之前，每次Flutter增加package后，运行debug，都要在“Running Gradle task ‘assembleDebug’”卡一阵
如何解决，网上大多数都提到更换maven源。
而有时实际情况是即使你换了，还是一个niaoyang。
直到发现了这篇文章： Flutter App stuck at "Running Gradle task 'assembleDebug'... "
处理方法如下:
1. Open your flutter Project directory.
2. Change directory to android directory in your flutter project directory `cd android`
3. clean gradle `./gradlew clean`
4. Build gradle `./gradlew build` or you can combine both commands with just `./gradlew clean build` (Thanks @daniel for the tip)
5. Now run your flutter project. If you use vscode, press F5. First time gradle running assembleDebug will take time.
执行gradlew clean后，会有下载jar的日志输出（下载了多少/jar多大）直观明了。
