code: public static MultipartContent multipart(final Consumer<MultipartContent> config) {
          MultipartContent content = new MultipartContent();
          config.accept(content);
          return content;
      }
docs: Configures multipart request content using a {@link Consumer} which will have an instance of {@link MultipartContent} passed into it for
  configuring the multipart content data.
  
  @param config the configuration {@link Consumer}
  @return a configured instance of {@link MultipartContent}