anchor.diff:    (with-accessors ((mux mux-of) (fds fds-of)
                      (timeouts timeouts-of)) event-base
       (let ((deletion-list ())
  -          (fd-events (harvest-events mux timeout)))
  +          (fd-events (harvest-events mux (or timeout *default-event-loop-timeout*))))
         (dolist (ev fd-events)
           (destructuring-bind (fd ev-types) ev
             (let ((fd-entry (fd-entry-of event-base fd)))
  
positive.code: 
  
  (defgeneric exit-event-loop (event-base &key delay)
    (:method ((event-base event-base) &key delay)
      (setf (main-timeout-of event-base)
            (add-timeout event-base
                         #'(lambda (fd event-type)
  
negative.code:    (main-timeout :initform nil
                   :accessor main-timeout-of)
     (exit :initform nil
           :accessor exit-p)
     (exit-when-empty :initarg :exit-when-empty
                      :accessor exit-when-empty-p))
    (:default-initargs :exit-when-empty nil))
  
  
  (defmethod print-object ((base event-base) stream)
  