*
   * <p><b>{@code Stream} equivalent:</b> {@code stream.filter(type::isInstance).map(type::cast)}.
   * This does perform a little more work than necessary, so another option is to insert an
   * unchecked cast at some later point:
   *
   * <pre>
   * {@code @SuppressWarnings("unchecked") // safe because of ::isInstance check
   * ImmutableList<NewType> result =

 *
 * <p>"IPv4 mapped" addresses were originally a representation of IPv4 addresses for use on an IPv6
 * socket that could receive both IPv4 and IPv6 connections (by disabling the {@code IPV6_V6ONLY}
 * socket option on an IPv6 socket). Yes, it's confusing. Nevertheless, these "mapped" addresses
 * were never supposed to be seen on the wire. That assumption was dropped, some say mistakenly, in

  private final ImmutableSet<TestOption> options;
  private boolean closed;

  public TestOutputStream(OutputStream out, TestOption... options) throws IOException {
    this(out, Arrays.asList(options));
  }

  public TestOutputStream(OutputStream out, Iterable<TestOption> options) throws IOException {
    super(checkNotNull(out));
    this.options = ImmutableSet.copyOf(options);
    throwIf(OPEN_THROWS);
  }

  private final ImmutableSet<TestOption> options;
  private boolean closed;

  public TestInputStream(InputStream in, TestOption... options) throws IOException {
    this(in, Arrays.asList(options));
  }

  public TestInputStream(InputStream in, Iterable<TestOption> options) throws IOException {
    super(checkNotNull(in));
    this.options = ImmutableSet.copyOf(options);
    throwIf(OPEN_THROWS);
  }

    sink.writeFrom(in);
    assertFalse(in.closed());
  }

  public void testClosesOnErrors_copyingFromByteSourceThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, READ_THROWS, CLOSE_THROWS)) {
      TestByteSource failSource = new TestByteSource(new byte[10], option);
      TestByteSink okSink = new TestByteSink();
      assertThrows(IOException.class, () -> failSource.copyTo(okSink));

    sink.writeFrom(in);
    assertFalse(in.closed());
  }

  public void testClosesOnErrors_copyingFromByteSourceThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, READ_THROWS, CLOSE_THROWS)) {
      TestByteSource failSource = new TestByteSource(new byte[10], option);
      TestByteSink okSink = new TestByteSink();
      assertThrows(IOException.class, () -> failSource.copyTo(okSink));

    assertFalse(out.closed());
  }

  public void testClosesOnErrors_copyingToByteSinkThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, WRITE_THROWS, CLOSE_THROWS)) {
      TestByteSource okSource = new TestByteSource(bytes);
      assertThrows(IOException.class, () -> okSource.copyTo(new TestByteSink(option)));
      // ensure stream was closed IF it was opened (depends on implementation whether or not it's

   *
   * <p>When the new X-Download-Options header is present with the value {@code noopen}, the user is
   * prevented from opening a file download directly; instead, they must first save the file
   * locally.
   *
   * @since 24.1
   */
  public static final String X_DOWNLOAD_OPTIONS = "X-Download-Options";

        getMultiset().setCount(e0(), 1, 5));
    expectContents(nCopies(3, e0()));
  }

  /*
   * TODO: test that unmodifiable multisets either throw UOE or return false
   * when both are valid options. Currently we test the UOE cases and the
   * return-false cases but not their intersection
   */

    for (int i = 0; i < reps; i++) {
      dummy ^= JOINER_ON_CHARACTER.join(components).length();
    }
    return dummy;
  }

  /**
   * Mimics what the {@link Joiner} class does internally when no extra options like ignoring {@code
   * null} values are used.
   */
  @Benchmark
  int joinerInlined(int reps) {
    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      StringBuilder sb = new StringBuilder();