feat: allow array block contain only length

[meandnano]

#264

[meandnano]

One question for another potential PR. Right now there's no way to configure avro.Writer inside ocf.Encoder. I guess it is possible to add writerConfig API field to ocf.encoderConfig with corresponding EncoderFunc and use this config while constructing avro.Writer inside ocf.NewEncoder.

[nrwiersma]

I assume it is to expose this option, in which case it would be added like WithBlockLength.

[nrwiersma]

LGTM 🎉

[meandnano]

I assume it is to expose this option, in which case it would be added like WithBlockLength.

I gave it another thought - ocf.WithBlockLength controls block length of the OCF file which is not the same as array/map block. And it is a feature of ocf.Encoder that logically resides above avro.Writer that is responsible for actual data encoding. Moreover, adding WithDisableBlockSizeHeader next to WithBlockLength in the ocf package might indeed be confusing.

Another point is that apart from DisableBlockSizeHeader there are other config fields which right now are locked by avro.DefaultConfig when writing OCF files.

Adding func WithWriterConfig(cfg API) EncoderFunc to ocf will allow to adjust any of them and thus have configurable encoder for OCF just as it is for plain messages.

What do you think?

UPD: Just realized the issue, API is in avro package and therefore cannot be accessed in ocf package without substantial refactoring. However ocf.WithWriter function seems like could be feasible solution... (tired at the end of working day)

[nrwiersma]

Sounds good to me

[meandnano]

Great, I can make PR tomorrow