Worked on the tokio-rs/tokio repository, delivering a public token accessor for DropGuard and DropGuardRef within the tokio-util crate. This feature exposed the underlying CancellationToken to client code, enabling more straightforward inspection and orchestration of cancellation logic in concurrent Rust applications. The implementation ensured safety by allowing token access only while the guard remained active, using expect to prevent misuse after drop. By reducing boilerplate and improving observability for cancellation-aware workflows, the work demonstrated a strong grasp of systems programming and concurrency patterns in Rust, focusing on practical API design and safe access to internal synchronization primitives.