code: public CacheManagerBuilder<T> using(Service service) {
      Set<Service> newServices = new HashSet<>(services);
      newServices.add(service);
      return new CacheManagerBuilder<>(this, newServices);
    }
docs: Adds a {@link Service} instance to the returned builder.
  <p>
  The service instance will be used by the constructed {@link CacheManager}.
  
  @param service the {@code Service} to add
  @return a new builder with the added service