} else {
        Entry<Cut<C>, Range<C>> lowerEntry =
            rangesByLowerBound.lowerEntry(upperBoundWindow.lowerEndpoint());
        if (lowerEntry == null) {
          backingItr = rangesByLowerBound.values().iterator();
        } else if (upperBoundWindow.lowerBound.isLessThan(lowerEntry.getValue().upperBound)) {
          backingItr = rangesByLowerBound.tailMap(lowerEntry.getKey(), true).values().iterator();
        } else {

  private Range<K> coalescedRange(Range<K> range, V value) {
    Range<K> coalescedRange = range;
    Entry<Cut<K>, RangeMapEntry<K, V>> lowerEntry =
        entriesByLowerBound.lowerEntry(range.lowerBound);
    coalescedRange = coalesce(coalescedRange, value, lowerEntry);

    Entry<Cut<K>, RangeMapEntry<K, V>> higherEntry =
        entriesByLowerBound.floorEntry(range.upperBound);

      return (NavigableMap<K, Collection<V>>) super.sortedMap();
    }

    @Override
    public @Nullable Entry<K, Collection<V>> lowerEntry(@ParametricNullness K key) {
      Entry<K, Collection<V>> entry = sortedMap().lowerEntry(key);
      return (entry == null) ? null : wrapEntry(entry);
    }

    @Override
    public @Nullable K lowerKey(@ParametricNullness K key) {