public void LoadData(IEnumerable <Build> builds) { var waitHandle = new CountdownEvent(1); var bulkAll = client.BulkAll(builds, b => b .Index <Build>() .BackOffRetries(2) .BackOffTime("30s") .MaxDegreeOfParallelism(4) .Size(1000) ); bulkAll.Subscribe(new BulkAllObserver( onNext: (b) => { Console.Write("."); }, onError: (e) => throw e, onCompleted: () => waitHandle.Signal() )); }