public Builder setOngoing(boolean ongoing) {
            setFlag(Notification.FLAG_ONGOING_EVENT, ongoing);
            return this;
        }
Set whether this is an ongoing notification.

<p>Ongoing notifications differ from regular notifications in the following ways:
<ul>
<li>Ongoing notifications are sorted above the regular notifications in the
notification panel.</li>
<li>Ongoing notifications do not have an 'X' close button, and are not affected
by the "Clear all" button.
</ul>
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/compat/NotificationCompat.java