abstract boolean casValue(AbstractFuture<?> future, @CheckForNull Object expect, Object update);
  }

  /**
   * {@link AtomicHelper} based on {@link sun.misc.Unsafe}.
   *
   * <p>Static initialization of this class will fail if the {@link sun.misc.Unsafe} object cannot
   * be accessed.
   */
  @SuppressWarnings({"sunapi", "removal"}) // b/318391980

  }

  static final Ticker NULL_TICKER =
      new Ticker() {
        @Override
        public long read() {
          return 0;
        }
      };

  // We use a holder class to delay initialization: https://github.com/google/guava/issues/6566
  private static final class LoggerHolder {
    static final Logger logger = Logger.getLogger(CacheBuilder.class.getName());
  }

  static final int UNSET_INT = -1;