text: public virtual java.util.NavigableSet<E> headSet(E end, bool endInclusive){java.util.Comparator<E> c = backingMap.comparator();if (c == null){((java.lang.Comparable<E>)end).compareTo(end);}else{c.compare(end, end);}return new java.util.TreeSet<E>(backingMap.headMap(end, endInclusive));}