anchor.diff:  
   (defun close-socket (socket)
     (let ((fd (iolib.sockets:socket-os-fd socket)))
  -    (ignore-errors (iomux:remove-fd-handlers *event-base* fd))
  +    (ignore-some-conditions (isys:syscall-error)
  +      (iomux:remove-fd-handlers *event-base* fd))
       (remove-socket socket)
       (close socket)))
   
  
positive.code:     (unwind-protect-case ()
          (progn
            (setf (iolib.streams:fd-non-blocking socket) t)
            (add-socket socket)
            (iomux:set-io-handler *event-base*
                                  (iolib.sockets:socket-os-fd socket)
                                  :read
  
negative.code:                 (progn
                    (setf *event-base* (make-instance 'iomux:event-base))
                    (with-open-stream (sock (start-echo-server host port))
                      (declare (ignore sock))
                      (iomux:event-dispatch *event-base* :timeout timeout)))
               (close-all-sockets)
               (close *event-base*))))
  