End ListenerSet iteration sooner

PiperOrigin-RevId: 384500287

library/common/src/main/java/com/google/android/exoplayer2/util/ListenerSet.java

@@ -179,7 +179,7 @@ public final class ListenerSet<T> {
       return;
     }
     if (!handler.hasMessages(MSG_ITERATION_FINISHED)) {
-      handler.obtainMessage(MSG_ITERATION_FINISHED).sendToTarget();
+      handler.sendMessageAtFrontOfQueue(handler.obtainMessage(MSG_ITERATION_FINISHED));
     }
     boolean recursiveFlushInProgress = !flushingEvents.isEmpty();
     flushingEvents.addAll(queuedEvents);

library/common/src/test/java/com/google/android/exoplayer2/util/ListenerSetTest.java

@@ -390,8 +390,8 @@ public class ListenerSetTest {
     // lazy release.
     verify(listener, times(3)).callback1();
     verify(listener).callback3();
-    verify(listener).iterationFinished(createFlagSet(EVENT_ID_1));
-    verify(listener).iterationFinished(createFlagSet(EVENT_ID_1, EVENT_ID_3));
+    verify(listener, times(2)).iterationFinished(createFlagSet(EVENT_ID_1));
+    verify(listener).iterationFinished(createFlagSet(EVENT_ID_3));
     verifyNoMoreInteractions(listener);
   }