Implement Eventuate Leadership APIs using a Kafka topic

Assignment of Partition 0 of 'leadership election topic' can be used to implement Eventuate leadership election as an alternative to Zookeeper.

Create a KafkaConsumer
Subscribe to a leadership topic with a ConsumerRebalanceListener
onPartitionsXXX() callbacks indicate whether partition 0 has been assigned, which indicates leadership

eventuate-foundation / eventuate-messaging-kafka