presto-orc/src/main/java/io/prestosql/orc/OrcWriteValidation.java/RowGroupStatistics/getColumnStatistics
class RowGroupStatistics:        public Map<OrcColumnId, ColumnStatistics> getColumnStatistics()
        {
            verify(validationMode != HASHED, "columnStatistics are not available in HASHED mode");
            return columnStatistics;
        }