Worked on enhancing streaming checkpointing reliability and delivery progress in the dotnet/orleans repository, focusing on more robust restart behavior and efficient checkpointing. Leveraged C# and asynchronous programming to introduce cancellable FlushAsync operations, improve latest-offset tracking, and implement per-subscription delivery-progress watermarks. Refactored the checkpoint flow to ensure monotonic, forward-only state updates and strengthened shutdown guarantees by persisting offsets before cache disposal. Expanded test coverage to validate edge cases such as rewinds and pending registrations, ensuring accurate and frequent checkpoints. The work improved the reliability and efficiency of the event-driven streaming system while reducing replay risk during recovery scenarios.