Flutter iOS 设备顶部状态栏亮度调整

在main函数内，调用SystemChrome.setSystemUIOverlayStyle方法，传入一个SystemUiOverlayStyle对象，设置您想要的颜色、亮度、图标等属性。例如，设置状态栏和操作栏为黑色，图标为亮色的代码是：

SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle(
  systemNavigationBarColor: Color(0xFF000000),
  systemNavigationBarIconBrightness: Brightness.light,
  statusBarIconBrightness: Brightness.dark
));