Dox constructor
      
      Dox()
     
    
    
Implementation
factory Dox() {
  if (_singleton == null) {
    Env().load();
    _singleton = Dox._internal();
  }
  return _singleton!;
}factory Dox() {
  if (_singleton == null) {
    Env().load();
    _singleton = Dox._internal();
  }
  return _singleton!;
}