presto-main/src/main/java/io/prestosql/sql/gen/OrderingCompiler.java/PagesIndexComparatorCacheKey/PagesIndexComparatorCacheKey
class PagesIndexComparatorCacheKey:        private PagesIndexComparatorCacheKey(List<Type> sortTypes, List<Integer> sortChannels, List<SortOrder> sortOrders)
        {
            this.sortTypes = ImmutableList.copyOf(sortTypes);
            this.sortChannels = ImmutableList.copyOf(sortChannels);
            this.sortOrders = ImmutableList.copyOf(sortOrders);
        }