haxe: Null object pattern for iterables

I'd like to implement Null Object design pattern for Iterable class. For example if my internal array isn't initialized, wrapper class anyway returns empty Iterator that doesn't break main logic:

public function iterator():Iterator<T> {
  // ...of cause it doesn't work, because Iterator is typedef not class
  return mList != null ? mList.iterator() : new Iterator<T>();
}

var mList:Array<T>;

Should I instantiate static empty dummy array with desired type of items or something else that implements Iterator interface but contains nothing? Or may be there is more straight solution?