code: public RestTemplateBuilder additionalMessageConverters(
  			Collection<? extends HttpMessageConverter<?>> messageConverters) {
  		Assert.notNull(messageConverters, "MessageConverters must not be null");
  		return new RestTemplateBuilder(this.detectRequestFactory, this.rootUri,
  				append(this.messageConverters, messageConverters),
  				this.requestFactorySupplier, this.uriTemplateHandler, this.errorHandler,
  				this.basicAuthentication, this.restTemplateCustomizers,
  				this.requestFactoryCustomizer, this.interceptors);
  	}
docs: Add additional {@link HttpMessageConverter HttpMessageConverters} that should be
  used with the {@link RestTemplate}. Any converters configured on the builder will
  replace RestTemplate's default converters.
  @param messageConverters the converters to add
  @return a new builder instance
  @see #messageConverters(HttpMessageConverter...)