saveImage method Null safety
- Uint8List image
 
Saves the image to the device.
Returns a Future<String>.
Implementation
static Future<String> saveImage(Uint8List image) async {
  await [Permission.storage].request();
  final timestamp = DateTime.now()
      .toIso8601String()
      .replaceAll('.', '-')
      .replaceAll(':', '-');
  final name = 'screenshot_$timestamp';
  final result = await ImageGallerySaver.saveImage(image, name: name);
  return result['filePath'];
}