presto-main/src/main/java/io/prestosql/operator/MultiChannelGroupByHash.java/GetRunLengthEncodedGroupIdsWork/GetRunLengthEncodedGroupIdsWork
class GetRunLengthEncodedGroupIdsWork:        public GetRunLengthEncodedGroupIdsWork(Page page)
        {
            this.page = requireNonNull(page, "page is null");
        }