anchor.diff:        (fulfill-plan/values future (multiple-value-list (funcall client-fn))))
       t))
   
  -(defmethod %force ((future %future))
  +(defun force-future (future)
     ;; If we are here then we've stolen the task from the kernel.
     (with-%future-slots (canceledp) future
       (setf canceledp t)
  
positive.code: `force' is called upon it."
    `(make-%delay-instance :fn (lambda () ,@body)))
  
  (defmethod %fulfill ((delay %delay) client-fn)
    (with-unfulfilled/no-wait delay
      (fulfill-plan/values delay (multiple-value-list (funcall client-fn)))
      t))
  
  (defmethod %force ((delay %delay))
    ;; do not use task handler
    (fulfill-plan/values
     delay (multiple-value-list (funcall (plan-fn delay)))))
  
  ;;;; future
  
  (defmethod %fulfill ((future %future) client-fn)
    (with-unfulfilled/no-wait future
      ;; If we are here then we've stolen the task from the kernel.
      (with-%future-slots (canceledp) future
  
negative.code: (defslots %chain ()
    ((object :reader chain-object)))
  
  ;;;; macros
  
  (defmacro with-lock-operation (operation promise &body body)
  