Worked on the apache/kafka repository to deliver two features focused on improving observability and API safety in Java-based Kafka consumer workflows. Developed a toString() method for KafkaMetric, enabling more readable and concise logging without exposing sensitive internal state. Introduced the RebalanceConsumer API, including a DelegatingRebalanceConsumer and enhanced ConsumerAwareRebalanceListener, to enforce safer lifecycle management during rebalance callbacks. These changes improved traceability and reliability in consumer rebalance operations, making debugging more straightforward and reducing the risk of misuse. The work demonstrated strong skills in Java, Kafka, and logging, with an emphasis on robust software development and unit testing practices.