final Iterator<Entry<K, Collection<V>>> backingIterator =
                unfiltered.asMap().entrySet().iterator();

            @Override
            @CheckForNull
            protected Entry<K, Collection<V>> computeNext() {
              while (backingIterator.hasNext()) {
                Entry<K, Collection<V>> entry = backingIterator.next();
                K key = entry.getKey();

            final Iterator<Entry<K, Collection<V>>> backingIterator =
                unfiltered.asMap().entrySet().iterator();

            @Override
            @CheckForNull
            protected Entry<K, Collection<V>> computeNext() {
              while (backingIterator.hasNext()) {
                Entry<K, Collection<V>> entry = backingIterator.next();
                K key = entry.getKey();

    @Override
    UnmodifiableIterator<Entry<K, ImmutableSet<V>>> entryIterator() {
      final Iterator<Entry<K, V>> backingIterator = ImmutableMap.this.entrySet().iterator();
      return new UnmodifiableIterator<Entry<K, ImmutableSet<V>>>() {
        @Override
        public boolean hasNext() {
          return backingIterator.hasNext();
        }

        @Override
        public Entry<K, ImmutableSet<V>> next() {

    @Override
    UnmodifiableIterator<Entry<K, ImmutableSet<V>>> entryIterator() {
      final Iterator<Entry<K, V>> backingIterator = ImmutableMap.this.entrySet().iterator();
      return new UnmodifiableIterator<Entry<K, ImmutableSet<V>>>() {
        @Override
        public boolean hasNext() {
          return backingIterator.hasNext();
        }

        @Override
        public Entry<K, ImmutableSet<V>> next() {