@RequiresApi(21)
        public Builder addInvisibleAction(int icon, CharSequence title, PendingIntent intent) {
            return addInvisibleAction(new Action(icon, title, intent));
        }
Add an invisible action to this notification. Invisible actions are never displayed by
the system, but can be retrieved and used by other application listening to
system notifications. Invisible actions are supported from Android 4.4.4 (API 20) and can
be retrieved using {@link NotificationCompat#getInvisibleActions(Notification)}.

@param icon   Resource ID of a drawable that represents the action.
@param title  Text describing the action.
@param intent {@link PendingIntent} to be fired when the action is invoked.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/compat/NotificationCompat.java