    # File lib/action_controller/reloader.rb, line 30
        def self.run(lock = @@default_lock)
          lock.lock
          begin
            Dispatcher.reload_application
            status, headers, body = yield
            # We do not want to call 'cleanup_application' in an ensure block
            # because the returned Rack response body may lazily generate its data. This
            # is for example the case if one calls
            #
            #   render :text => lambda { ... code here which refers to application models ... }
            #
            # in an ActionController.
            #
            # Instead, we will want to cleanup the application code after the request is
            # completely finished. So we wrap the body in a BodyWrapper class so that
            # when the Rack handler calls #close during the end of the request, we get to
            # run our cleanup code.
            [status, headers, BodyWrapper.new(body, lock)]
          rescue Exception
            lock.unlock
            raise
          end
        end