code: public static <T> String join(Iterator<T> iterator) {
          return new JoinStrings<T>().apply(iterator);
      }
docs: Joins an iterator of T into a String. E.g: <code>[1,2,3] -> "123"</code>
  
  @param <T> the iterator element type
  @param iterator the iterator to be joined
  @return the resulting string