Github user nickwallen commented on the issue:
https://github.com/apache/metron/pull/1045
I noticed that we should probably use a timeout when we call
`KafkaProducer.close`. If we get a huge backlog of messages, it will just
block until the backlog is cleared. We can get in situations where we build-up
such a large backlog that there just is no hope of clearing it. This might
actually explain why some of the topologies just won't die sometimes.---
