@gdusbabek The idea was to store the object of `KafkaProducer` which is like the wrapper class for `Producer` in the field `instance` and then call method `pushRollup` on that object. So when we are pushing the roll-up to Kafka in `RollupRunnable` we are using `KafkaProducer.getInstance().pushRollup(...)`. Is using this singleton pattern not the right way to go?