return Observable.create(
                new ObservableOnSubscribe<Response>() {
                    OkHttpClient client = new OkHttpClient();

                     @Override
                     public void subscribe(ObservableEmitter<Response> emitter) throws Exception {
                         try {
                             Response response = client.newCall(new Request.Builder().url(url).build()).execute();
                             emitter.onNext(response);
                             emitter.onComplete();
                             if (!response.isSuccessful()) emitter.onError(new Exception("error"));
                         } catch (IOException e) {
                             emitter.onError(e);
                         }

                     }
        })
        .subscribeOn(Schedulers.io());