phone static method
Generate a random phone number.
Implementation
static String phone([String countryCode = '+84']) {
final part1 = _random.nextInt(900) + 100; // 100-999
final part2 = _random.nextInt(900) + 100; // 100-999
final part3 = _random.nextInt(900) + 100; // 0000-9999
return '$countryCode-$part1-$part2-${part3.toString().padLeft(3, '0')}';
}