flutter 获取图片尺寸

int imageWidth;
int imageHeight;
Image imageNetwork = Image(image: new CachedNetworkImageProvider("url");
imageNetwork.image.resolve(ImageConfiguration()).addListener(
  ImageStreamListener(
    (ImageInfo info, bool _) {
      imageWidth = info.image.width;
      imageHeight = info.image.height；
    },
  ),
);