During this period, contributed to the swiftlang/swift-foundation repository by addressing a critical resource management issue in Windows file-mapping. Focused on improving memory management and file I/O reliability, the work involved correcting the deallocation logic for .alwaysMapped file mappings to ensure the mapping handle, rather than the mapped view pointer, is used during unmapping. This targeted bug fix, implemented in Swift and leveraging the Windows API, prevents resource leaks and enhances the stability of applications relying on mapped files. The solution reduced potential leak paths in Windows builds, reflecting a careful approach to low-level systems programming and cross-platform compatibility.