assertTrue(segment.recencyQueue.isEmpty());

        for (int i = 0; i < DRAIN_THRESHOLD / 2; i++) {
          map.get(keyOne);
        }
        assertFalse(segment.recencyQueue.isEmpty());

        for (int i = 0; i < DRAIN_THRESHOLD * 2; i++) {
          map.get(keyOne);
          assertTrue(segment.recencyQueue.size() <= DRAIN_THRESHOLD);
        }

        // get over many different keys

        assertTrue(segment.recencyQueue.isEmpty());

        for (int i = 0; i < DRAIN_THRESHOLD / 2; i++) {
          map.get(keyOne);
        }
        assertFalse(segment.recencyQueue.isEmpty());

        for (int i = 0; i < DRAIN_THRESHOLD * 2; i++) {
          map.get(keyOne);
          assertTrue(segment.recencyQueue.size() <= DRAIN_THRESHOLD);
        }

        // get over many different keys

   *
   * <p>This must be a (2^n)-1 as it is used as a mask.
   */
  static final int DRAIN_THRESHOLD = 0x3F;

  /**
   * Maximum number of entries to be drained in a single cleanup run. This applies independently to
   * the cleanup queue and both reference queues.
   */
  // TODO(fry): empirically optimize this
  static final int DRAIN_MAX = 16;

  // Fields

   *
   * <p>This must be a (2^n)-1 as it is used as a mask.
   */
  static final int DRAIN_THRESHOLD = 0x3F;

  /**
   * Maximum number of entries to be drained in a single cleanup run. This applies independently to
   * the cleanup queue and both reference queues.
   */
  // TODO(fry): empirically optimize this
  static final int DRAIN_MAX = 16;

  // Fields