}

    @Override
    public boolean hasNext() {
      return !stack.isEmpty();
    }

    @Override
    public T next() {
      Iterator<T> itr = stack.getLast(); // throws NSEE if empty
      T result = checkNotNull(itr.next());
      if (!itr.hasNext()) {
        stack.removeLast();
      }
      Iterator<T> childItr = children(result).iterator();
      if (childItr.hasNext()) {

    Iterator<Range<C>> itr = rangeSet.asRanges().iterator();
    Range<C> expectedSpan = null;
    if (itr.hasNext()) {
      expectedSpan = itr.next();
      while (itr.hasNext()) {
        expectedSpan = expectedSpan.span(itr.next());
      }
    }

    try {
      Range<C> span = rangeSet.span();
      assertEquals(expectedSpan, span);
    } catch (NoSuchElementException e) {

     */
    void add(Problem.Severity severity, String message, int line, int column, Exception cause);

    /**
     * The next messages will be bound to this source. When calling this method again, previous messages keep
     * their source, but the next messages will use the new source.
     *
     * @param source a source
     */
    void setSource(String source);

    /**
     *

         *
         * @return number of retry attempts
         */
        public int getRetryCount() {
            return retryCount;
        }

        /**
         * Get next retry time
         *
         * @return time of next retry attempt
         */
        public long getNextRetryTime() {
            return nextRetryTime;
        }

        /**
         * Check if recovery should be attempted

      String nextSeparator = "";
      StringBuilder builder = new StringBuilder(32).append(className).append('{');
      for (ValueHolder valueHolder = holderHead.next;
          valueHolder != null;
          valueHolder = valueHolder.next) {
        Object value = valueHolder.value;
        if (valueHolder instanceof UnconditionalValueHolder
            || (value == null
                ? !omitNullValuesSnapshot

        backingItr.next();
      }
      return new AbstractIterator<Entry<Cut<C>, Range<C>>>() {
        @Override
        protected @Nullable Entry<Cut<C>, Range<C>> computeNext() {
          if (!backingItr.hasNext()) {
            return endOfData();
          }
          Range<C> range = backingItr.next();
          return upperBoundWindow.lowerBound.isLessThan(range.upperBound)

  }

  @CollectionFeature.Require({SUPPORTS_ADD, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
  public void testSetCountZeroToOneConcurrentWithEntrySetIteration() {
    Iterator<Entry<E>> iterator = getMultiset().entrySet().iterator();
    assertSetCount(e3(), 1);
    assertThrows(ConcurrentModificationException.class, iterator::next);
  }

    private final ReferenceEntry<K, V> next;

    public DummyEntry(K key, int hash, ReferenceEntry<K, V> next) {
      this.key = key;
      this.hash = hash;
      this.next = next;
    }

    public static <K, V> DummyEntry<K, V> create(
        K key, int hash, @Nullable ReferenceEntry<K, V> next) {
      return new DummyEntry<>(key, hash, next);
    }

    public void clearKey() {

        throw new ClUnsupportedOperationException("remove");
    }

    @Override
    public boolean hasNext() {
        return false;
    }

    @Override
    public T next() {
        throw new ClUnsupportedOperationException("next");
    }

    if (!newRouteSelector.hasNext()) throw IOException("exhausted all routes")
    val newRouteSelection = newRouteSelector.next()
    routeSelection = newRouteSelection

    if (isCanceled()) throw IOException("Canceled")

    return planConnectToRoute(newRouteSelection.next(), newRouteSelection.routes)
  }

  /**
   * Returns a plan to reuse a pooled connection, or null if the pool doesn't have a connection for