// away, as can connectWriteOrder, nullifyWriteOrder.
      newEntry.setWriteTime(original.getWriteTime());

      connectWriteOrder(original.getPreviousInWriteQueue(), newEntry);
      connectWriteOrder(newEntry, original.getNextInWriteQueue());

      nullifyWriteOrder(original);
    }
  }

  /** A reference to a value. */
  interface ValueReference<K, V> {