public void forEach(Consumer<? super T> action) {
        checkNotNull(action);
        new Consumer<T>() {
          @Override
          public void accept(T t) {
            action.accept(t);
            children(t).forEach(this);
          }
        }.accept(root);
      }
    };
  }

  UnmodifiableIterator<T> preOrderIterator(T root) {
    return new PreOrderIterator(root);
  }

        .newBuilder(server.url("/").toUri())
        .header("Accept", "text/plain")
        .build()

    val response = httpClient.send(request, BodyHandlers.ofString())
    assertThat(response.statusCode()).isEqualTo(200)
    assertThat(response.body()).isEqualTo("hello, Java HTTP Client")

    val recorded = server.takeRequest()
    assertThat(recorded.headers["Accept"]).isEqualTo("text/plain")

    if (streamA.isParallel() || streamB.isParallel()) {
      zip(streamA, streamB, TemporaryPair::new).forEach(pair -> consumer.accept(pair.a, pair.b));
    } else {
      Iterator<A> iterA = streamA.iterator();
      Iterator<B> iterB = streamB.iterator();
      while (iterA.hasNext() && iterB.hasNext()) {
        consumer.accept(iterA.next(), iterB.next());
      }
    }
  }

  /**
   * Invokes {@code latch.}{@link CountDownLatch#await(long, TimeUnit) await(timeout, unit)}
   * uninterruptibly.
   */
  @J2ktIncompatible
  @GwtIncompatible // concurrency
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public static boolean awaitUninterruptibly(CountDownLatch latch, long timeout, TimeUnit unit) {
    boolean interrupted = false;
    try {
      long remainingNanos = unit.toNanos(timeout);

  /** The HTTP {@code Accept} header field name. */
  public static final String ACCEPT = "Accept";

  /** The HTTP {@code Accept-Charset} header field name. */
  public static final String ACCEPT_CHARSET = "Accept-Charset";

  /** The HTTP {@code Accept-Encoding} header field name. */
  public static final String ACCEPT_ENCODING = "Accept-Encoding";

  /** The HTTP {@code Accept-Language} header field name. */

        .url(server.url("/"))
        .header("Accept", "text/plain")
        .build()
    val response = client.newCall(request).execute()
    assertThat(response.code).isEqualTo(200)
    assertThat(response.body.string()).isEqualTo("hello, OkHttp")

    val recorded = server.takeRequest()
    assertThat(recorded.headers["Accept"]).isEqualTo("text/plain")
    assertThat(recorded.headers["Accept-Encoding"]).isEqualTo("gzip")

      .assertNoMoreLogs()
    networkLogs
      .assertLogEqual("--> GET $url http/1.1")
      .assertLogEqual("Host: $host")
      .assertLogEqual("Connection: Keep-Alive")
      .assertLogEqual("Accept-Encoding: gzip")
      .assertLogMatch(Regex("""User-Agent: okhttp/.+"""))
      .assertLogEqual("--> END GET")
      .assertLogMatch(Regex("""<-- 200 OK $url \(\d+ms\)"""))
      .assertLogEqual("Content-Length: 0")

    val request = HttpGet(server.url("/").toUri())
    request.addHeader("Accept", "text/plain")

    httpClient.execute(request).use { response ->
      assertThat(response.code).isEqualTo(200)
      assertThat(EntityUtils.toString(response.entity)).isEqualTo("hello, Apache HttpClient 5.x")
    }

    val recorded = server.takeRequest()
    assertThat(recorded.headers["Accept"]).isEqualTo("text/plain")

  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  @CanIgnoreReturnValue
  public FakeTicker advance(long time, TimeUnit timeUnit) {
    return advance(timeUnit.toNanos(time));
  }

  /** Advances the ticker value by {@code nanoseconds}. */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  @CanIgnoreReturnValue
  public FakeTicker advance(long nanoseconds) {

   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *
   * @deprecated Prefer {@linkplain UncheckedExecutionException(Throwable)} a constructor that
   *     accepts a cause: Users of this class typically expect for instances to have a non-null
   *     cause. At the moment, you can <i>usually</i> still preserve behavior by passing an explicit