return new AbstractIterator<Entry<K, V>>() {
        private int index = -1;
        private final int maxIndex = keyToIndex().size();

        @Override
        @CheckForNull
        protected Entry<K, V> computeNext() {
          for (index++; index < maxIndex; index++) {
            V value = getValue(index);
            if (value != null) {
              return Maps.immutableEntry(getKey(index), value);
            }

      return new AbstractIterator<Entry<K, V>>() {
        private int index = -1;
        private final int maxIndex = keyToIndex().size();

        @Override
        @CheckForNull
        protected Entry<K, V> computeNext() {
          for (index++; index < maxIndex; index++) {
            V value = getValue(index);
            if (value != null) {
              return Maps.immutableEntry(getKey(index), value);
            }