code: function deserializeKafkaMessage(kafkaMessage) {
      kafkaMessage.message = objectFactory(kafkaMessage.value);
  
      kafkaMessage.message._kafka = {
          topic:     kafkaMessage.topic,
          partition: kafkaMessage.partition,
          offset:    kafkaMessage.offset,
          timestamp: kafkaMessage.timestamp || null,
          key:       kafkaMessage.key,
      };
  
      return kafkaMessage;
  }
docs: Parses kafkaMessage.message as a JSON string and then
  augments the object with kafka message metadata.
  in the message._kafka sub object.
  
  @param  {KafkaMesssage} kafkaMessage
  @return {Object}