docs: public static <T> ServiceFuture<T> fromResponse(final Observable<ServiceResponse<T>> observable, final ServiceCallback<T> callback) {
          final ServiceFuture<T> serviceFuture = new ServiceFuture<>();
          serviceFuture.subscription = observable
                  .last()
                  .subscribe(new Action1<ServiceResponse<T>>() {
                      @Override
                      public void call(ServiceResponse<T> t) {
                          if (callback != null) {
                              callback.success(t.body());
                          }
                          serviceFuture.set(t.body());
                      }
                  }, new Action1<Throwable>() {
                      @Override
                      public void call(Throwable throwable) {
                          if (callback != null) {
                              callback.failure(throwable);
                          }
                          serviceFuture.setException(throwable);
                      }
                  });
          return serviceFuture;
      }