public static @Nullable Insets getCustomButtonInsets(Component c) {
    if (!(c instanceof AbstractButton b)) return null;

    Object maybeInsets = b.getClientProperty("customButtonInsets");
    if (!(maybeInsets instanceof Insets)) return null;

    return ((Insets)maybeInsets);
  }
public static @Nullable Insets getCustomButtonInsets(Component c)