Worked on enhancing Fuchsia event handling within the dart-lang/sdk repository, focusing on improving asynchronous cancellation in the Dart SDK. Leveraged C++ and system programming skills to implement zx_port_cancel_key, which streamlined the IOHandle lifecycle and eliminated the need to manage original handles directly. This architectural change reduced memory management risks and simplified cancellation logic in event-driven programming scenarios. The update improved the reliability of asynchronous waits and made future maintenance more straightforward. All modifications were validated through local testing in the test embedder, ensuring robust integration. The work laid a foundation for scalable, maintainable event handling in Fuchsia environments.