code: public HttpWebServiceMessageSenderBuilder requestFactory(
  			Supplier<ClientHttpRequestFactory> requestFactorySupplier) {
  		Assert.notNull(requestFactorySupplier,
  				"RequestFactory Supplier must not be null");
  		this.requestFactorySupplier = requestFactorySupplier;
  		return this;
  	}
docs: Set the {@code Supplier} of {@link ClientHttpRequestFactory} that should be called
  to create the HTTP-based {@link WebServiceMessageSender}.
  @param requestFactorySupplier the supplier for the request factory
  @return a new builder instance