Worked on stability improvements for the apache/pulsar project, focusing on the broker acknowledgment path when ackReceipt is enabled. Addressed a critical bug that caused blocking in the acknowledgeCumulativeAsync method, ensuring that cumulative acknowledgments remain non-blocking under high-throughput scenarios. Developed and integrated targeted verification tests, such as testAckReceipt, to validate correct handling of ack receipts and maintain asynchronous processing. Utilized Java for backend development and testing, applying expertise in messaging systems to enhance broker reliability. The work emphasized robust validation and careful testing, prioritizing system stability over new feature development during the period covered by this profile.