Implement single response publisher methods

   <R> CompletionStage<R> compose(Function<? super Publisher<T>, ? extends CompletionStage<R>> transformer,
         Function<? super Publisher<R>, ? extends CompletionStage<R>> finalizer);

      java.util.function.Function<Publisher<?>, CompletionStage<Long>> transformer = cp ->
            Flowable.fromPublisher(cp)
                  .count()
                  .to(RxJavaInterop.singleToCompletionStage());
      java.util.function.Function<Publisher<Long>, CompletionStage<Long>> finalizer = results ->
            Flowable.fromPublisher(results)
                  .reduce((long) 0, Long::sum)
                  .to(RxJavaInterop.singleToCompletionStage());
      return infinispanPublisher.compose(transformer, finalizer);