*
   * @param x the value
   * @param hc the hash code holder
   * @param wasUncontended false if CAS failed before call
   */
  final void retryUpdate(long x, int @Nullable [] hc, boolean wasUncontended) {
    int h;
    if (hc == null) {
      threadHashCode.set(hc = new int[1]); // Initialize randomly
      int r = rng.nextInt(); // Avoid zero to allow xorShift rehash
      h = hc[0] = (r == 0) ? 1 : r;
    } else h = hc[0];