Kafka producer does not propagate error when unable to connect to broker

[Thomas Weise <th...@apache.org>]

I noticed that when the Kafka output operator (0.9) is configured with a
wrong port or missing the security setup required by the cluster, it will
be in "ACTIVE" state but not do anything, essentially ignoring the error.

I see that part of the problem is that the producer is async. That makes me
wonder how we actually can make any assertions about the processing
guarantee of this operator?

Thanks,
Thomas