consumer is hard coded to return byte keys and byte values

[darkone23]

The new producer code is generic to the kafka producer you provide and configurable through the producer config.

The kafka consumer code is also generic and allows passing in a key and value decoder, but kafka-rx doesn't let you configure these parameters and only uses the default byte decoders.

It would be nice if both sides were generic and allowed users to provide their own codec classes. This way you wouldn't have to manually map your byte decoder over your stream every time you consume.