NotEnoughReplicasError and NotEnoughReplicasAfterAppendError should be retriable.

[varunl]

According to the kafka protocol doc, the errors NOT_ENOUGH_REPLICAS and NOT_ENOUGH_REPLICAS_AFTER_APPEND, error codes 19 and 20 respectively, should be retriable.

I don't see them as retriable in the code. Is there a reason for that?

[varunl]

@dpkp Any insight into this?

[dpkp]

likely an oversight. PRs welcome!