YARN-8404. Timeline event publish need to be async to avoid Dispatcher thread leak in case ATS is down. Contributed by Rohith Sharma K S

(cherry picked from commit 6307962b932e0ee69ba61f5796388c175d79195a)
(cherry picked from commit 96a6798c1ddbfc159e50f1a2049754898156dbe3)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/TimelineServiceV1Publisher.java

@@ -151,9 +151,9 @@ public class TimelineServiceV1Publisher extends AbstractSystemMetricsPublisher {
     tEvent.setEventInfo(eventInfo);
 
     entity.addEvent(tEvent);
-    // sync sending of finish event to avoid possibility of saving application
-    // finished state in RMStateStore save without publishing in ATS.
-    putEntity(entity); // sync event so that ATS update is done without fail.
+
+    getDispatcher().getEventHandler().handle(new TimelineV1PublishEvent(
+        SystemMetricsEventType.PUBLISH_ENTITY, entity, app.getApplicationId()));
   }
 
   @SuppressWarnings("unchecked")