December 2025: Delivered two high-impact fixes to enhance determinism, reliability, and production stability across two core repositories. mathworks/arrow replaced std::multimap::find with std::multimap::equal_range for duplicate keys, ensuring predictable results and reducing nondeterminism; envoyproxy/envoy fixed inconsistent retrieval of request IDs from client metadata when multiple entries exist. Both changes include unit tests and align with standard library best practices, reducing bug surface and simplifying debugging in production. Demonstrated skills include advanced C++, STL containers, equal_range usage, unit testing, and cross-repo collaboration. Business value: more reliable metadata handling, fewer hard-to-reproduce bugs, and improved maintainability across services.