Worked on the firebase/firebase-android-sdk repository, focusing on improving app reliability and performance by addressing a critical Application Not Responding (ANR) issue. The solution involved modifying SharedPreferencesQueue to use the asynchronous apply() method instead of commit(), which reduced lock contention and prevented background thread blocking on disk I/O. This approach maintained update order by synchronizing in-memory state, ensuring data consistency while enhancing responsiveness. The work demonstrated strong skills in Android development, Java, and concurrency management. By resolving this bug, the developer contributed to a smoother user experience for applications relying on Firebase Cloud Messaging and SharedPreferences within the Android ecosystem.