public Message messageForRegistrant() {
        Handler h = getHandler();

        if (h == null) {
            clear();

            return null;
        } else {
            Message msg = h.obtainMessage();

            msg.what = what;
            msg.obj = userObj;

            return msg;
        }
    }
NOTE: May return null if weak reference has been collected
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/os/async/Registrant.java