    # File lib/action_controller/test_process.rb, line 398
        def xml_http_request(request_method, action, parameters = nil, session = nil, flash = nil)
          @request.env['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
          @request.env['HTTP_ACCEPT'] = 'text/javascript, text/html, application/xml, text/xml, */*'
          returning send!(request_method, action, parameters, session, flash) do
            @request.env.delete 'HTTP_X_REQUESTED_WITH'
            @request.env.delete 'HTTP_ACCEPT'
          end
        end