@Override
        public void onBlobDeleted(String blobId, String serviceId, Account account, Container container) {
          blobsThatAreDeleted.put(blobId, serviceId);
          deletesDoneLatch.countDown();
        }
Test that even when a composite blob put succeeds, the slipped put data chunks are deleted.
Background deleter hits Replica_Unavailable and swallow the error.
ambry-router/src/test/java/com/github/ambry/router/NonBlockingRouterTest.java