May 2026 (2026-05) monthly summary for typelevel/cats-effect. Focused on two high-impact improvements in performance and code quality, with clear business value and preserved backward compatibility. Key features delivered: - Performance optimization for the cancellation path: Refactored the Uncancelable trait by moving the IdPoll object into the MonadCancel object, reducing memory allocations while preserving backward compatibility. Commit: dcba7ab3a66f1431bbc16f119962cda0ab922d5f. - Improved readability and maintainability of error handling: Refactored showUnknown to remove unnecessary string interpolation and renamed a local variable to reflect its purpose as an error, improving clarity and consistency. Commit: cfcf921ce0ca3c16f073ed7d2a290682ed7a96be. Major bugs fixed: - No separate bug fixes recorded for this month. The emphasis was on performance and readability improvements that reduce allocation pressure and enhance maintainability. Overall impact and accomplishments: - Reduced allocation pressure in critical cancellation code paths, contributing to potential throughput gains under high-cancellation workloads. - Improved code clarity and maintainability, reducing future maintenance cost and risk of regressions. - Backward compatibility preserved throughout the refactors, ensuring stable adoption in downstream users. Technologies/skills demonstrated: - Scala and functional programming patterns, memory allocation optimization, code refactoring, and clarity improvements in error handling. - Attention to backward compatibility and maintainability during performance-focused changes.