*/
  @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() {

   * the {@link Multimap} interface.
   */
  @CanIgnoreReturnValue
  @Override
  List<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values);

  /**
   * {@inheritDoc}
   *
   * <p><b>Note:</b> The returned map's values are guaranteed to be of type {@link List}. To obtain

   * the {@link Multimap} interface.
   */
  @CanIgnoreReturnValue
  @Override
  List<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values);

  /**
   * {@inheritDoc}
   *
   * <p><b>Note:</b> The returned map's values are guaranteed to be of type {@link List}. To obtain

    public String toString() {
      return "ByteSource.empty()";
    }
  }

  private static final class ConcatenatedByteSource extends ByteSource {

    final Iterable<? extends ByteSource> sources;

    ConcatenatedByteSource(Iterable<? extends ByteSource> sources) {
      this.sources = checkNotNull(sources);
    }

    @Override
    public InputStream openStream() throws IOException {

      return arithmetic.toString();
    }
  }

  private interface ParameterTypesDifferent {
    void foo(
        String s,
        Runnable r,
        Number n,
        Iterable<?> it,
        boolean b,
        Equivalence<String> eq,
        Exception e,
        InputStream in,
        Comparable<?> c,
        Ordering<Integer> ord,
        Charset charset,

   * <? extends Object> is mostly the same as <?> to plain Java. But to nullness checkers, they
   * differ: <? extends Object> means "non-null types," while <?> means "all types."
   */
  ImmutableMap<K, V> getAllPresent(Iterable<? extends Object> keys);

  /**
   * Associates {@code value} with {@code key} in this cache. If the cache previously contained a
   * value associated with {@code key}, the old value is replaced by {@code value}.
   *

   * actual implementation tests are further down.
   */

  public abstract static class AbstractFilteredIterableTest<C extends Iterable<Integer>>
      extends TestCase {
    abstract C createUnfiltered(Iterable<Integer> contents);

    abstract C filter(C elements, Predicate<? super Integer> predicate);

    public void testIterationOrderPreserved() {

    list.add("a");
    try {
      assertEmpty(list);
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
    try {
      assertEmpty(
          new Iterable<String>() {
            @Override
            public Iterator<String> iterator() {
              return singleton("a").iterator();
            }
          });
      throw new Error();

    list.add("a");
    try {
      assertEmpty(list);
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
    try {
      assertEmpty(
          new Iterable<String>() {
            @Override
            public Iterator<String> iterator() {
              return singleton("a").iterator();
            }
          });
      throw new Error();

            reloadCount.incrementAndGet();
            return immediateFuture(new Object());
          }

          @Override
          public Map<Object, Object> loadAll(Iterable<?> keys) {
            loadAllCount.incrementAndGet();
            return ImmutableMap.of();
          }
        };

    assertThat(loadCount.get()).isEqualTo(0);
    assertThat(reloadCount.get()).isEqualTo(0);