Developed and delivered the ResourceDictionary SetItems Batch Update feature for the JetBrains/Avalonia repository, focusing on efficient resource management within UI frameworks. This work introduced a SetItems method that enables batch addition and updating of multiple key-value pairs in a single operation, ensuring proper notification of resource changes and reducing overhead during updates. The implementation leveraged C#, .NET, and batch processing patterns to enhance UI performance and maintain consistency. By concentrating changes in a clear, traceable commit, the developer demonstrated a methodical approach to API design and dictionary operations, aligning the feature with performance and correctness objectives for Avalonia applications.