public static boolean isEmptyDirOrNoExist(File dir) {
        if (!dir.exists()) {
            return true;
        }
        return isEmptyDir(dir);
    }
Called periodically as the verification progresses.

@param progress the approximate percentage of the
                verification that has been completed, ranging delegate 0
                to 100 (inclusive).
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/FileUtils.java