presto-redis/src/main/java/io/prestosql/plugin/redis/RedisMetadata.java/RedisMetadata/appendFields
class RedisMetadata:    private static void appendFields(ImmutableList.Builder<ColumnMetadata> builder, RedisTableFieldGroup group)
    {
        if (group != null) {
            List<RedisTableFieldDescription> fields = group.getFields();
            if (fields != null) {
                for (RedisTableFieldDescription fieldDescription : fields) {
                    builder.add(fieldDescription.getColumnMetadata());
                }
            }
        }
    }