Failed assertion: line 3180 pos 12: ‘debugNeedsPaint‘: is not true

进行flutter 点击截图 调用第一次截图方法报错
Failed assertion: line 3180 pos 12: ‘debugNeedsPaint’: is not true.

flutter: 'package:flutter/src/rendering/proxy_box.dart': Failed assertion: line 3180 pos 12: '!debugNeedsPaint': is not true.

解决方案:
在调用截图方法的时候增加一个延时调用即可

 onPressed: () {
    
    
                Future.delayed(Duration.zero, () {
    
    
                  this._capturePng();
                });
              },