/** Most of the tests in this class run against every one of these caches. */
  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Object, Object>>() {

   */
  @CanIgnoreReturnValue
  public B withFeatures(Feature<?>... features) {
    return withFeatures(asList(features));
  }

  @CanIgnoreReturnValue
  public B withFeatures(Iterable<? extends Feature<?>> features) {
    for (Feature<?> feature : features) {
      this.features.add(feature);
    }
    return self();
  }

  public Set<Feature<?>> getFeatures() {

   * <p>If the {@link Path} passed to one of the traversal methods does not exist or is not a
   * directory, no exception will be thrown and the returned {@link Iterable} will contain a single
   * element: that path.
   *
   * <p>{@link DirectoryIteratorException} may be thrown when iterating {@link Iterable} instances
   * created by this traverser if an {@link IOException} is thrown by a call to {@link
   * #listFiles(Path)}.
   *

   * <p>If the {@link Path} passed to one of the traversal methods does not exist or is not a
   * directory, no exception will be thrown and the returned {@link Iterable} will contain a single
   * element: that path.
   *
   * <p>{@link DirectoryIteratorException} may be thrown when iterating {@link Iterable} instances
   * created by this traverser if an {@link IOException} is thrown by a call to {@link
   * #listFiles(Path)}.
   *

    }
    @Nullable Object[] result = new Object[length];
    arraycopy(elements, offset, result, 0, length);
    return result;
  }

  @CanIgnoreReturnValue
  private static @Nullable Object[] fillArray(Iterable<?> elements, @Nullable Object[] array) {
    int i = 0;
    for (Object element : elements) {
      array[i++] = element;
    }
    return array;
  }

      boolean sameComparator,
      Iterable<? extends Entry<? extends K, ? extends V>> entries) {
    // "adding" type params to an array of a raw type should be safe as
    // long as no one can ever cast that same array instance back to a
    // raw type.
    @SuppressWarnings("unchecked")
    Entry<K, V>[] entryArray = (Entry[]) Iterables.toArray(entries, EMPTY_ENTRY_ARRAY);

          .put(PeekingIterator.class, Iterators.peekingIterator(ImmutableSet.of().iterator()))
          .put(ListIterator.class, ImmutableList.of().listIterator())
          .put(Iterable.class, ImmutableSet.of())
          .put(Collection.class, ImmutableList.of())
          .put(ImmutableCollection.class, ImmutableList.of())
          .put(List.class, ImmutableList.of())

   *
   * @param values a series of values, which will be converted to {@code double} values (this may
   *     cause loss of precision)
   */
  public static Stats of(Iterable<? extends Number> values) {
    StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(values);
    return accumulator.snapshot();
  }

  /**

   * entries in the same order as the original iterable.
   *
   * @throws NullPointerException if any key, value, or entry is null
   * @throws IllegalArgumentException if two entries have the same key
   * @since 19.0
   */
  public static <K, V> ImmutableMap<K, V> copyOf(
      Iterable<? extends Entry<? extends K, ? extends V>> entries) {

    }
  }

  private static final ImmutableList<Double> FINITE_TOLERANCE_CANDIDATES =
      ImmutableList.of(-0.0, 0.0, 1.0, 100.0, 10000.0, Double.MAX_VALUE);

  private static final Iterable<Double> TOLERANCE_CANDIDATES =
      Iterables.concat(FINITE_TOLERANCE_CANDIDATES, ImmutableList.of(Double.POSITIVE_INFINITY));

  private static final List<Double> BAD_TOLERANCE_CANDIDATES =
      Doubles.asList(
          -Double.MIN_VALUE,