Fix TransactionalProducer implementation once Confluent driver support this

[IgorFedchenko]

There are couple of TODO labels in TransactionalProducerStage.cs file (in TransactionalProducerStageLogic class implementation). This is due to lack of transactional operations support in Confluent driver's producer implementation.

This also requires some librdkafka update. The issue to track is https://github.com/confluentinc/confluent-kafka-dotnet/issues/1091.

Once this will be ready, implementation should work (there is a test at TransactionalIntegrationTests.cs that is skipped right now).

[IgorFedchenko]

Looks like they have published update which includes transaction support: https://www.nuget.org/packages/Confluent.Kafka/1.4.0

So now we can implement missing transactional stages.

[chris-sung]

ah, this is a long waiting feature that I'm waiting to be implemented

[IgorFedchenko]

@chris-sung Yeah, the problem is that _producer.InitTransactions call to Confluent driver is blocking for some reason, and I can't make my PR passing tests. And I ran out of time, not able to fix it now... If you will have time and willing to check it out or fork my branch and play with this, you are wellcome :)

Otherwise it may take a long time to have this working...

[rafalpiotrowski]

Hi, Is this resolved now? or still pending?

[IgorFedchenko]

Hey, nope, this is not resolved - there is a PR (https://github.com/akkadotnet/Akka.Streams.Kafka/pull/196) which was never finished (see comments above). Probably it will work now with latest driver versions, not sure.