@Override
  protected int normalizePriority(int priority) {
    // no one can have higher priority than meta transition.
    if (priority >= META_TRANSITION_QOS) {
      return META_TRANSITION_QOS - 1;
    } else {
      return priority;
    }
  }
We reference this value in SimpleRpcScheduler so this class have to be public instead of
package private
hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterAnnotationReadingPriorityFunction.java