@VisibleForTesting @CheckForNull transient @Nullable Object[] elements;

  /**
   * Keeps track of metadata like the number of hash table bits and modifications of this data
   * structure (to make it possible to throw ConcurrentModificationException in the iterator). Note
   * that we choose not to make this volatile, so we do less of a "best effort" to track such
   * errors, for better performance.
   */
  private transient int metadata;

                    }
                  },
                  service);
        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {

                    }
                  },
                  service);
        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {

   * a request itself.
   *
   * @since 31.0
   */
  public static final String X_DEVICE_REQUESTED_WITH = "X-Device-Requested-With";
  /** The HTTP {@code X-Do-Not-Track} header field name. */
  public static final String X_DO_NOT_TRACK = "X-Do-Not-Track";
  /** The HTTP {@code X-Forwarded-For} header field name (superseded by {@code Forwarded}). */
  public static final String X_FORWARDED_FOR = "X-Forwarded-For";

  @VisibleForTesting @CheckForNull transient @Nullable Object[] values;

  /**
   * Keeps track of metadata like the number of hash table bits and modifications of this data
   * structure (to make it possible to throw ConcurrentModificationException in the iterator). Note
   * that we choose not to make this volatile, so we do less of a "best effort" to track such
   * errors, for better performance.
   *

              [INFO] Validating units:
              [INFO]    Ignored 53 units with compilation errors in first pass.
              [INFO] Compile with -strict or with -logLevel set to TRACE or DEBUG to see all errors.

            Turning up the log level, we see that GWT is trying to compile classes from other
            packages, like RangeTest. The reason for this is that GWT doesn't distinguish between

    @CheckForNull private Iterator<? extends T> toRemove;

    /* The iterator currently returning elements. */
    private Iterator<? extends T> iterator;

    /*
     * We track the "meta iterators," the iterators-of-iterators, below.  Usually, topMetaIterator
     * is the only one in use, but if we encounter nested concatenations, we start a deque of

  /**
   * As described in <a href="https://w3c.github.io/webvtt/#iana-text-vtt">the VTT spec</a>, this is
   * used for Web Video Text Tracks (WebVTT) files, used with the HTML5 track element.
   *
   * @since 20.0
   */
  public static final MediaType VTT_UTF_8 = createConstantUtf8(TEXT_TYPE, "vtt");

  /* image types */
  /**