(define var 22)
(define s (delay (lambda () (sleep 3) (set! var 9))))
(define (my-delay-eval)
  (+ 1 1)
  (parallel-execute (force s) (lambda () (list 33)))
  (+ 2 3))
(my-delay-eval) => 5
var => 22
三秒后 var => 9