// creating an ArrayList so filtering happens once
      return Lists.newArrayList(iterator()).toArray();
    }

    @Override
    @SuppressWarnings("nullness") // b/192354773 in our checker affects toArray declarations
    public <T extends @Nullable Object> T[] toArray(T[] array) {
      return Lists.newArrayList(iterator()).toArray(array);
    }
  }

  /**

   * perform well, {@code function} should be fast. To avoid lazy evaluation when the returned
   * multimap doesn't need to be a view, copy the returned multimap into a new multimap of your
   * choosing.
   *
   * @since 7.0
   */
  public static <
          K extends @Nullable Object, V1 extends @Nullable Object, V2 extends @Nullable Object>
      Multimap<K, V2> transformValues(

   * perform well, {@code function} should be fast. To avoid lazy evaluation when the returned
   * multimap doesn't need to be a view, copy the returned multimap into a new multimap of your
   * choosing.
   *
   * @since 7.0
   */
  public static <
          K extends @Nullable Object, V1 extends @Nullable Object, V2 extends @Nullable Object>
      Multimap<K, V2> transformValues(

 * reference. It allows you to represent "a {@code T} that must be present" and a "a {@code T} that
 * might be absent" as two distinct types in your program, which can aid clarity.
 *
 * <p>Some uses of this class include
 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no
 *       value was available

        .address.url.host
    ) {
      return true // This connection is a perfect match.
    }

    // At this point we don't have a hostname match. But we still be able to carry the request if
    // our connection coalescing requirements are met. See also:
    // https://hpbn.co/optimizing-application-delivery/#eliminate-domain-sharding
    // https://daniel.haxx.se/blog/2016/08/18/http2-connection-coalescing/

 * </ul>
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableListMultimap}
 *   <li>{@link ImmutableSetMultimap}
 *   <li>Configure your own mutable multimap with {@link MultimapBuilder}
 *   <li>{@link LinkedListMultimap} (for one unusual kind of mutable {@code Multimap})
 * </ul>
 *

    @SuppressWarnings("SynchronizeOnNonFinalField")
    public T get() {
      // Another variant of Double Checked Locking.
      //
      // We use two volatile reads. We could reduce this to one by
      // putting our fields into a holder class, but (at least on x86)
      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;

 * </ul>
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableListMultimap}
 *   <li>{@link ImmutableSetMultimap}
 *   <li>Configure your own mutable multimap with {@link MultimapBuilder}
 *   <li>{@link LinkedListMultimap} (for one unusual kind of mutable {@code Multimap})
 * </ul>
 *

  public static <T extends @Nullable Object> Iterable<T> concat(
      Iterable<? extends T> a, Iterable<? extends T> b, Iterable<? extends T> c) {
    return FluentIterable.concat(a, b, c);
  }

  /**
   * Combines four iterables into a single iterable. The returned iterable has an iterator that
   * traverses the elements in {@code a}, followed by the elements in {@code b}, followed by the

    }
  }

  public void testMappedIPv4Addresses() throws UnknownHostException {
    /*
     * Verify that it is not possible to instantiate an Inet6Address
     * from an "IPv4 mapped" IPv6 address.  Our String-based method can
     * at least identify them, however.
     */
    String mappedStr = "::ffff:192.168.0.1";
    assertTrue(InetAddresses.isMappedIPv4Address(mappedStr));