anchor.diff:  (defclass route (routes:route)
     ((symbol :initarg :symbol :reader route-symbol)
      (submodule :initarg :submodule :initform nil)
  -   (content-type :initarg :content-type :initform nil :reader route-content-type)
      (required-method :initarg :required-method :initform nil :reader route-required-method)
      (arbitrary-requirement :initarg :arbitrary-requirement :initform nil :reader route-arbitrary-requirement)
  -   (render-method :initarg :render-method :initform #'identity)))
  +   (render-method :initarg :render-method :initform #'identity)
  +   (headers :initarg :headers :initform nil :reader route-headers)))
   
   (defun route-render-method (route)
     (or (slot-value route 'render-method)
  
positive.code:     (multiple-value-bind (route bindings) (routes:match mapper url)
        (if route
            (alexandria:alist-plist bindings)))))
    
negative.code:                                        content-type
                                         render-method
                                         requirement
                                         parse-vars
  				       headers)
                          &body body)
    (let* ((variables (iter (for var in (routes:template-variables (routes:parse-template template)))
                            (collect (list (intern (symbol-name var))
  