protected int getAnnotatedPriority(RequestHeader header) {
    String methodName = header.getMethodName();
    Integer priorityByAnnotation = annotatedQos.get(methodName);
    if (priorityByAnnotation != null) {
      return normalizePriority(priorityByAnnotation);
    }
    return -1;
  }
See if the method has an annotation.
@return Return the priority from the annotation. If there isn't an annotation, this returns
        something below zero.
hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/AnnotationReadingPriorityFunction.java