*
   * @param expect the expected value
   * @param update the new value
   * @return {@code true} if successful
   */
  public final boolean weakCompareAndSet(double expect, double update) {
    return updater.weakCompareAndSet(
        this, doubleToRawLongBits(expect), doubleToRawLongBits(update));
  }

  /**
   * Atomically adds the given value to the current value.
   *