formatSize(double? value, {int fixed = 2}) {
  if (value == 0) return "0M";
  List<String> unitArr = ['B', 'K', 'M', 'G'];
  int index = 0;
  while (value! > 1024) {
    index++;
    value = value/ 1024;
  }
  String size = value.toStringAsFixed(fixed);
  return size + unitArr[index];
}

toString(double? value, {int fractionDigits = 1}){
  if(value == null)return "";
  if(value.toInt() == value)return value.toStringAsFixed(0);
  else return value.toStringAsFixed(fractionDigits);
}