}
        result = size = Ints.saturatedCast(total);
      }
      return result.intValue();
    }

    @Override
    public UnmodifiableIterator<C> iterator() {
      return new AbstractIterator<C>() {
        final Iterator<Range<C>> rangeItr = ranges.iterator();
        Iterator<C> elemItr = Iterators.emptyIterator();

        @Override
        @CheckForNull
        protected C computeNext() {

        Iterators.mergeSorted(
            Iterables.transform(
                backingMap.values(), (Map<C, V> input) -> input.keySet().iterator()),
            comparator);

    return new AbstractIterator<C>() {
      @CheckForNull C lastValue;

      @Override
      @CheckForNull
      protected C computeNext() {
        while (merged.hasNext()) {
          C next = merged.next();

        @Override
        Map<K, Collection<V>> map() {
          return AsMap.this;
        }

        @Override
        public Iterator<Entry<K, Collection<V>>> iterator() {
          return new AbstractIterator<Entry<K, Collection<V>>>() {
            final Iterator<Entry<K, Collection<V>>> backingIterator =
                unfiltered.asMap().entrySet().iterator();

            @Override
            @CheckForNull

      final Iterable<? extends Optional<? extends T>> optionals) {
    checkNotNull(optionals);
    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return new AbstractIterator<T>() {
          private final Iterator<? extends Optional<? extends T>> iterator =
              checkNotNull(optionals.iterator());

          @Override
          @CheckForNull

      final Iterable<? extends Optional<? extends T>> optionals) {
    checkNotNull(optionals);
    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return new AbstractIterator<T>() {
          private final Iterator<? extends Optional<? extends T>> iterator =
              checkNotNull(optionals.iterator());

          @Override
          @CheckForNull

    }
  }

  private interface Strategy {
    Iterator<String> iterator(Splitter splitter, CharSequence toSplit);
  }

  private abstract static class SplittingIterator extends AbstractIterator<String> {
    final CharSequence toSplit;
    final CharMatcher trimmer;
    final boolean omitEmptyStrings;

    /**

    }
  }

  private interface Strategy {
    Iterator<String> iterator(Splitter splitter, CharSequence toSplit);
  }

  private abstract static class SplittingIterator extends AbstractIterator<String> {
    final CharSequence toSplit;
    final CharMatcher trimmer;
    final boolean omitEmptyStrings;

    /**

  public static <T extends @Nullable Object> UnmodifiableIterator<T> filter(
      Iterator<T> unfiltered, Predicate<? super T> retainIfTrue) {
    checkNotNull(unfiltered);
    checkNotNull(retainIfTrue);
    return new AbstractIterator<T>() {
      @Override
      @CheckForNull
      protected T computeNext() {
        while (unfiltered.hasNext()) {
          T element = unfiltered.next();
          if (retainIfTrue.apply(element)) {

  public static <T extends @Nullable Object> UnmodifiableIterator<T> filter(
      Iterator<T> unfiltered, Predicate<? super T> retainIfTrue) {
    checkNotNull(unfiltered);
    checkNotNull(retainIfTrue);
    return new AbstractIterator<T>() {
      @Override
      @CheckForNull
      protected T computeNext() {
        while (unfiltered.hasNext()) {
          T element = unfiltered.next();
          if (retainIfTrue.apply(element)) {