instance method call

# File actionpack/lib/action_controller/dispatcher.rb, line 104
    def call(env)
      if @@cache_classes
        @app.call(env)
      else
        Reloader.run do
          # When class reloading is turned on, we will want to rebuild the
          # middleware stack every time we process a request. If we don't
          # rebuild the middleware stack, then the stack may contain references
          # to old classes metal classes, which will b0rk class reloading.
          build_middleware_stack
          @app.call(env)
        end
      end
    end