resolver method
- required String name,
 
Implementation
Future<String?> resolver({required String name}) async {
  final function = abi.getFunction('resolver')!;
  final node = namehash(name);
  try {
    final result = await readSafe(
      function: function.addValues(values: [node]),
    );
    final resolver = result.outputs.first.value as String;
    if (resolver == nullAddress) {
      return null;
    }
    return resolver;
  } on RangeError {
    return null;
  }
}