如何使Haskell的TChan延迟邮件像Erlang的消息队列？

-module(testit).
-export([testit/0]).

testit() ->
    Pid = spawn(fun testit_proc/0),Pid ! final,Pid ! one,Pid ! two,io:format("Root finished~n").

testit_proc() ->
    receive
        one     -> io:format("One~n");
        two     -> io:format("Two~n")
    end,receive
        one     -> io:format("One~n");
        two     -> io:format("Two~n")
    end,receive
        one     -> io:format("One~n");
        two     -> io:format("Two~n");
        final   -> io:format("Final~n")
    end,io:format("Spawn finished~n").

输出为：

Root finished
One
Two
Final
Spawn finished

最终消息的处理基本上延迟到最后接收块之前,因为先前的接收模式不匹配该消息.

你怎么用Haskell的TChan这样做？