method changed

Source

void changed(String key) {
  if (_permission == Permission.NONE) {
    return;
  }

  if (key.startsWith(r'$$')) {
    if (_permission < Permission.CONFIG) {
      return;
    }
    if (key.startsWith(r'$$$')) {
      return;
    }
  }

  if (changes.isEmpty) {
    changes.add(key);
    prepareSending();
  } else {
    changes.add(key);
  }
}