class KafkaClusterObserver implements Closeable {

  public KafkaClusterObserver(String bootstrapServer) {
    Properties properties = new Properties();
    properties.setProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServer);
    properties.setProperty(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, String.valueOf(false));
    properties.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
        DESERIALIZER_CLASS);
    properties.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
        DESERIALIZER_CLASS);
    this.kafkaConsumer = new KafkaConsumer(properties);
  }

  public  KafkaClusterObserver(String bootstrapServer);
  @VisibleForTesting protected  KafkaClusterObserver(KafkaConsumer kafkaConsumer);

}