downloadImageAsset method
Downloads the image from the Flutter assets into the printer under the specified file name,
Implementation
//Future<Image> downloadImageAsset(String assetKey,
Future<bool> downloadImageAsset(String assetKey,
{int x = 0, int y = 0, double scale = 1, int printerDpi = 203}) async {
Image image = await BrotherUtils.loadImage(assetKey);
return downloadImage(image,
x: x, y: y, scale: scale, printerDpi: printerDpi);
}