lazyUpdate method
Implementation
@override
void lazyUpdate(VoidCallback c, [String? d, VoidCallback? afterUpdate]) {
WidgetsBinding.instance.addPostFrameCallback((dt){
debugUpdate(c, d);
//// 实现 onMeasured 生命周期的关键
if(afterUpdate != null){
WidgetsBinding.instance.addPostFrameCallback((_)=>afterUpdate());
}
});
}