public Map<Long, ActiveRequest> getActiveRequestMap() {
    return activeRequestMap;
  }
Maps {@link StageEntityPK} of all ongoing requests to its {@link ActiveStage}
with updated {@link ActiveStage#status} and {@link ActiveStage#displayStatus}.
ambari-server/src/main/java/org/apache/ambari/server/events/listeners/tasks/TaskStatusListener.java