code: public static <T extends Item> Iterable<T> allItems(ItemGroup root, Class<T> type) {
          return allItems(Jenkins.getAuthentication(), root, type);
      }
docs: Gets a read-only view of all the {@link Item}s recursively in the {@link ItemGroup} tree visible to
  {@link Jenkins#getAuthentication()} without concern for the order in which items are returned. Each iteration
  of the view will be "live" reflecting the items available between the time the iteration was started and the
  time the iteration was completed, however if items are moved during an iteration - depending on the move - it
  may be possible for such items to escape the entire iteration.
  
  @param root the root.
  @param type the type.
  @param <T> the type.
  @return An {@link Iterable} for all items.
  @since 2.37