Developed a feature enhancement for the JetBrains/Avalonia repository, focusing on improving the UniformGrid control by introducing row and column spacing properties. This work involved updating the layout pipeline, specifically the MeasureOverride and ArrangeOverride methods, to ensure that spacing was accurately reflected during both measurement and arrangement phases. Leveraging skills in layout management, UI development, and unit testing with C#, the developer added comprehensive unit tests to validate the new spacing behavior across various grid configurations. The enhancement aimed to increase layout precision and developer productivity, while also improving test coverage and reliability within the Avalonia UI framework.