把函数转成深层处理器的续体

文档中深层处理器的例子有这么一段。

计算 f 本身也可以执行效果。当 f 执行 Yield 时，它的任务被暂停并放入就绪任务队列，然后调度器运行队列中的下一个任务。如果效果是 Fork f，就暂停当前任务，通过尾调用 spawn f 立即运行新任务 f。要注意，先运行新任务只是一个任意的选择。也可以把 f 的任务放进就绪队列，然后立即继续 k。

也许我漏掉了什么简单的东西，但看看这个调度器例子。

type _ Effect.t += Fork : (unit -> unit) -> unit t
                 | Yield : unit t

(* Round-robin scheduling with concurrency *)
let run (entry : unit -> unit) : unit =
  let pending : (int * (int, unit) continuation) option ref =
    ref None (* exchanger awaiting a partner *)
  in
  let ready = Queue.create () in (* ready-task queue *)
  let schedule cont arg =
    let resume () = continue cont arg in
    Queue.push
      resume ready
  in
  let next () =
    if Queue.is_empty ready then () (* finished *)
    else begin
      let resume = Queue.pop ready in
      resume ()
    end
  in
  let rec start (work : unit -> unit) : unit =
    match work () with
    | () -> next ()
    | exception err ->
        print_endline (Printexc.to_string err);
        next ()
    | effect Yield, cont -> schedule cont (); next ()
    (* How can work be queued at this point? *)
    | effect (Fork work), cont -> schedule cont (); start work
    | effect (Xchg value), cont ->
        begin match !pending with
        | Some (other, saved) -> pending := None; schedule saved value; continue cont other
        | None -> pending := Some (value, cont); next ()
        end
  in
  start entry

要怎样把 work 放进 ready？