Support writing native parquet

[anoopnarang]

Hi,

Got to know about columnify (https://github.com/reproio/columnify) from https://github.com/fluent/fluent-plugin-s3/blob/master/docs/output.md#compress-for-parquet-compressor-only-section

Does columnify supports writing native parquet without having explicit schema in avro file ?

I want to use the same with fluent-plugin-s3.