code: public GrpcServiceBuilder addServices(Iterable<BindableService> bindableServices) {
          requireNonNull(bindableServices, "bindableServices");
          bindableServices.forEach(this::addService);
          return this;
      }
docs: Adds gRPC {@link BindableService}s to this {@link GrpcServiceBuilder}. Most gRPC service
  implementations are {@link BindableService}s.