Lan Nguyen contributed to the DataDog/dd-sdk-android repository by enhancing session replay stability and modularity within the Android SDK. Lan refactored the FixedWindowCallback component, originally part of the RUM module, to address a null menu crash and improve window focus handling, eliminating brittle try-catch overrides. By relocating FixedWindowCallback to an internal utilities module and introducing a compileOnly dependency, Lan enabled its reuse across modules without requiring the full RUM dependency, reducing coupling and deployment surface. This work, implemented in Java and Kotlin, demonstrated a thoughtful approach to architectural modularity and maintainability, aligning with broader engineering goals for the SDK.