public Builder setLights(@ColorInt int argb, int onMs, int offMs) {
            mNotification.ledARGB = argb;
            mNotification.ledOnMS = onMs;
            mNotification.ledOffMS = offMs;
            boolean showLights = mNotification.ledOnMS != 0 && mNotification.ledOffMS != 0;
            mNotification.flags = (mNotification.flags & ~Notification.FLAG_SHOW_LIGHTS) |
                    (showLights ? Notification.FLAG_SHOW_LIGHTS : 0);
            return this;
        }
Set the argb value that you would like the LED on the device to blink, as well as the
rate.  The rate is specified in terms of the number of milliseconds to be on
and then the number of milliseconds to be off.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/compat/NotificationCompat.java