// Queues

  /**
   * A custom queue for managing eviction order. Note that this is tightly integrated with {@code
   * ReferenceEntry}, upon which it relies to perform its linking.
   *
   * <p>Note that this entire implementation makes the assumption that all elements which are in the
   * map are also in this queue, and that all elements not in the queue are not in the map.
   *

  }

  /**
   * Creates a <i>mutable</i>, empty {@code HashMap} instance.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableMap#of()} instead.
   *
   * <p><b>Note:</b> if {@code K} is an {@code enum} type, use {@link #newEnumMap} instead.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated. Instead,

  // Queues

  /**
   * A custom queue for managing eviction order. Note that this is tightly integrated with {@code
   * ReferenceEntry}, upon which it relies to perform its linking.
   *
   * <p>Note that this entire implementation makes the assumption that all elements which are in the
   * map are also in this queue, and that all elements not in the queue are not in the map.
   *

     * {@link CloseableList} may not be subsumed.
     */
    CLOSING,

    /** The {@link CloseableList} has been closed. It may not be further subsumed. */
    CLOSED,

    /**
     * {@link ClosingFuture#finishToValueAndCloser(ValueAndCloserConsumer, Executor)} has been