static <K> boolean casTabAt(Node<K>[] tab, int i, Node<K> c, Node<K> v) {
    return U.compareAndSwapObject(tab, ((long) i << ASHIFT) + ABASE, c, v);
  }
Returns k.compareTo(x) if x matches kc (k's screened comparable class), else 0.
geode-core/src/main/java/org/apache/geode/internal/concurrent/CompactConcurrentHashSet2.java