private static String format(String text, @Nullable Object... args) {
    return args == null ? text : String.format(Locale.US, text, args);
  }
Pass a semi-transparency color (e.g., 0x66RRGGBB) to give the overlay a color shade.
drawee/src/main/java/com/facebook/drawee/debug/DebugControllerOverlayDrawable.java