render_with_a_layout

# File actionpack/lib/action_controller/layout.rb, line 244
      def render_with_a_layout(options = nil, extra_options = {}, &block) #:nodoc:
        template_with_options = options.is_a?(Hash)

        if (layout = pick_layout(template_with_options, options)) && apply_layout?(template_with_options, options)
          options = options.merge :layout => false if template_with_options
          logger.info("Rendering template within #{layout}") if logger

          content_for_layout = render_with_no_layout(options, extra_options, &block)
          erase_render_results
          add_variables_to_assigns
          @template.instance_variable_set("@content_for_layout", content_for_layout)
          response.layout = layout
          status = template_with_options ? options[:status] : nil
          render_for_text(@template.render_file(layout, true), status)
        else
          render_with_no_layout(options, extra_options, &block)
        end
      end