code: public RestTemplateBuilder customizers(
  			Collection<? extends RestTemplateCustomizer> restTemplateCustomizers) {
  		Assert.notNull(restTemplateCustomizers,
  				"RestTemplateCustomizers must not be null");
  		return new RestTemplateBuilder(this.detectRequestFactory, this.rootUri,
  				this.messageConverters, this.requestFactorySupplier,
  				this.uriTemplateHandler, this.errorHandler, this.basicAuthentication,
  				Collections.unmodifiableSet(new LinkedHashSet<RestTemplateCustomizer>(
  						restTemplateCustomizers)),
  				this.requestFactoryCustomizer, this.interceptors);
  	}
docs: Set the {@link RestTemplateCustomizer RestTemplateCustomizers} that should be
  applied to the {@link RestTemplate}. Customizers are applied in the order that they
  were added after builder configuration has been applied. Setting this value will
  replace any previously configured customizers.
  @param restTemplateCustomizers the customizers to set
  @return a new builder instance
  @see #additionalCustomizers(RestTemplateCustomizer...)