else if (a.cas(v = a.value, fn(v, x))) break;
        else if (n >= NCPU || cells != as) collide = false; // At max size or stale
        else if (!collide) collide = true;
        else if (busy == 0 && casBusy()) {
          try {
            if (cells == as) { // Expand table unless stale
              Cell[] rs = new Cell[n << 1];
              for (int i = 0; i < n; ++i) rs[i] = as[i];
              cells = rs;

   * implementation; otherwise refreshes will be performed during unrelated cache read and write
   * operations.
   *
   * <p>Currently automatic refreshes are performed when the first stale request for an entry
   * occurs. The request triggering refresh will make a synchronous call to {@link
   * CacheLoader#reload}
   * and immediately return the new value if the returned future is complete, and the old value

  }

  /**
   * Gets the value from an entry. Returns null if the entry is invalid, partially-collected,
   * loading, or expired. Unlike {@link Segment#getLiveValue} this method does not attempt to clean
   * up stale entries. As such it should only be called outside a segment context, such as during
   * iteration.
   */
  @CheckForNull
  V getLiveValue(ReferenceEntry<K, V> entry, long now) {
    if (entry.getKey() == null) {

   *
   * <p>Zero is treated as having log2 == 0.
   */
  static double randomDouble(int maxExponent) {
    double result = RANDOM_SOURCE.nextDouble();
    result = Math.scalb(result, RANDOM_SOURCE.nextInt(maxExponent + 1));
    return RANDOM_SOURCE.nextBoolean() ? result : -result;
  }

  /** Returns a random integer between zero and {@code MAX_EXPONENT}. */
  static int randomExponent() {