presto-main/src/main/java/io/prestosql/operator/index/PageRecordSet.java/PageRecordSet/PageRecordCursor
class PageRecordSet:        private PageRecordCursor(List<Type> types, Page page)
        {
            this.types = ImmutableList.copyOf(requireNonNull(types, "types is null"));
            this.page = requireNonNull(page, "page is null");
            checkArgument(types.size() == page.getChannelCount(), "Types do not match page channels");
        }