public Builder setSortKey(String sortKey) {
            mSortKey = sortKey;
            return this;
        }
Set a sort key that orders this notification among other notifications from the
same package. This can be useful if an external sort was already applied and an app
would like to preserve this. Notifications will be sorted lexicographically using this
value, although providing different priorities in addition to providing sort key may
cause this value to be ignored.

<p>This sort key can also be used to order members of a notification group. See
{@link Builder#setGroup}.

@see String#compareTo(String)
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/compat/NotificationCompat.java