presto-hive/src/main/java/io/prestosql/plugin/hive/s3select/S3SelectRecordCursor.java/S3SelectRecordCursor/buildColumnTypes
class S3SelectRecordCursor:    private static String buildColumnTypes(List<HiveColumnHandle> columns)
    {
        if (columns == null || columns.isEmpty()) {
            return "";
        }
        return columns.stream()
                .map(column -> column.getHiveType().getTypeInfo().getTypeName())
                .collect(Collectors.joining(","));
    }