/**
     * Returns the entry associated with this value reference, or {@code null} if this value
     * reference is independent of any entry.
     */
    @CheckForNull
    ReferenceEntry<K, V> getEntry();

    /**
     * Creates a copy of this reference for the given entry.
     *
     * <p>{@code value} may be null only for a loading reference.
     */
    ValueReference<K, V> copyFor(

    /**
     * Returns the entry associated with this value reference, or {@code null} if this value
     * reference is independent of any entry.
     */
    @CheckForNull
    ReferenceEntry<K, V> getEntry();

    /**
     * Creates a copy of this reference for the given entry.
     *
     * <p>{@code value} may be null only for a loading reference.
     */
    ValueReference<K, V> copyFor(

   * they all succeed. If any fail, the resulting pipeline will fail.
   *
   * <p>Calling this method allows you to use lambdas or method references typed with the types of
   * the input {@link ClosingFuture}s.
   *
   * @throws IllegalStateException if a {@code ClosingFuture} has already been derived from any of

    future2 = null;

    /*
     * Futures should be collected even if combiner never runs. This is kind of a silly test, since
     * the combiner is almost certain to hold its own reference to the futures, and a real app would
     * hold a reference to the executor and thus to the combiner. What we really care about is that
     * the futures are released once the combiner is done running. But we happen to provide this

    future2 = null;

    /*
     * Futures should be collected even if combiner never runs. This is kind of a silly test, since
     * the combiner is almost certain to hold its own reference to the futures, and a real app would
     * hold a reference to the executor and thus to the combiner. What we really care about is that
     * the futures are released once the combiner is done running. But we happen to provide this

        map.put(keyOne, valueOne);
        ReferenceEntry<Object, Object> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));

        map.put(keyOne, valueOne);
        ReferenceEntry<Object, Object> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));