Worked on stability and correctness improvements in the AvaloniaUI/angle repository, focusing on external fence synchronization within graphics APIs. Addressed a crash scenario by implementing robust validation in the ExternalFence SyncWaitFd logic, ensuring that invalid file descriptors, such as those returned by vkGetFenceFdKHR or eglDupNativeFenceFDANDROID, are properly guarded against. Enhanced error handling and defensive programming practices in C++ to prevent SyncWaitFd from being called with invalid descriptors, thereby improving reliability. Updated the test suite to cover these edge cases, strengthening overall test coverage. The work demonstrated strong debugging skills and a deep understanding of EGL and Vulkan integration.