code: public static List<IItem> getAllItems(List<IItem> items, boolean countHeaders, IPredicate predicate) {
          return getAllItems(items, countHeaders, false, predicate);
      }
docs: retrieves a flat list of the items in the provided list, respecting subitems regardless of there current visibility
  
  @param items        the list of items to process
  @param countHeaders if true, headers will be counted as well
  @return list of items in the adapter