@Override
    public String put(String key, String value) {
        String res = mStorage.put(key, value == null ? NULL_INDICATOR : value);
        mHandler.removeCallbacks(mFlushCaller);
        mHandler.postDelayed(mFlushCaller, FLUSH_DELAY);
        return res;
    }
Flush data too many times, may drain battery.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/persist/StringMapRepo.java