    # File lib/action_controller/middleware_stack.rb, line 14
          def initialize(klass, *args, &block)
            @klass = klass

            options = args.extract_options!
            if options.has_key?(:if)
              @conditional = options.delete(:if)
            else
              @conditional = true
            end
            args << options unless options.empty?

            @args = args
            @block = block
          end