anchor.diff:                      &aux
                       send-seq send-data send-data-length
                       (send-retries *socket-sync-retries*)
  -                    recv-message recv-seq
  +                    recv-message recv-seq recv-data
                       (sockets (list socket)))
     "sync messages on single socket"
     (declare (type usocket:datagram-usocket socket))
  
positive.code:                (declare (ignore return-sockets))
                 real-time))
             (recv ()
               (let ((recv-data (usocket:socket-receive socket nil max-receive-length)))
                 (when recv-data
                   (multiple-value-setq (recv-message recv-seq)
                     (funcall decode-function recv-data))
                   (= send-seq recv-seq)))))
  
negative.code:   (multiple-value-setq (send-data send-seq)
      (funcall encode-function message))
    (setq send-data-length (length send-data))
    (setq recv-data (make-array max-receive-length
                                :element-type '(unsigned-byte 8)
                                :initial-element 0))
    ;; Define basic network operations
    (labels ((send ()
               (let ((nbytes (usocket:socket-send socket send-data send-data-length)))
  