(define clock:offset-from-server
(lambda (server-proc local-proc)
(let* ((t1 (clock:clock))
(t2 (ipc:call server-proc local-proc 'clock:clock))
(t3 t2)
(t4 (clock:clock))
(msg-delay (- (- t4 t1) (- t2 t3)))
(time-offset (/ (+ (- t2 t1) (- t3 t4)) 2)))
time-offset)))