public KeySpliterator<K,V> trySplit() {
            int i, f, h;
            return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
                new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
                                        f, est >>>= 1);
        }
public KeySpliterator<K,V> trySplit()