Ordering<Object> arbitrary = Ordering.arbitrary();
    Object[] array = {1, "foo", new Object()};

    // There's no way to tell what the order should be except empirically
    Arrays.sort(array, arbitrary);
    testExhaustively(arbitrary, array);
  }

  /**
   * Requires at least 3 elements in {@code strictlyOrderedElements} in order to test the varargs
   * version of min/max.

    Ordering<Object> arbitrary = Ordering.arbitrary();
    Object[] array = {1, "foo", new Object()};

    // There's no way to tell what the order should be except empirically
    Arrays.sort(array, arbitrary);
    testExhaustively(arbitrary, array);
  }

  /**
   * Requires at least 3 elements in {@code strictlyOrderedElements} in order to test the varargs
   * version of min/max.

  /**
   * 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

  /**
   * Mask value for indexing into segments. The upper bits of a key's hash code are used to choose
   * the segment.
   */