formatSize function
Format size strings like "500MB" into bytes
Implementation
String formatSize(int bytes) {
if (bytes >= 1 << 30) return '${(bytes / (1 << 30)).toStringAsFixed(2)} GB';
if (bytes >= 1 << 20) return '${(bytes / (1 << 20)).toStringAsFixed(2)} MB';
if (bytes >= 1 << 10) return '${(bytes / (1 << 10)).toStringAsFixed(2)} KB';
return '$bytes B';
}