Merge pull request ReactiveX#628 from mattrjacobs/fix-merge-delay-error

Properly wired up SynchronizedObserver within MergeDelayError operator

Author: mattrjacobs

rxjava-core/src/main/java/rx/operators/OperationMergeDelayError.java

@@ -168,7 +168,7 @@ public Subscription onSubscribe(Observer<? super T> actualObserver) {
             /**
              * Subscribe to the parent Observable to get to the children Observables
              */
-            completeSubscription.add(sequences.subscribe(new ParentObserver(actualObserver)));
+            completeSubscription.add(sequences.subscribe(new ParentObserver(synchronizedObserver)));
 
             /* return our subscription to allow unsubscribing */
             return completeSubscription;