Atomic updates

[cal]

On Tuesday, 22 January 2013 at 08:12:03 UTC, qznc wrote:
> On Tuesday, 22 January 2013 at 00:10:22 UTC, bearophile wrote:
>> I suggest to put your code on Rosettacode now, and then we'll 
>> do the changes there... As you see in other answers, both me 
>> and monarch_dodra have other ideas for improvements.
>
> Ok, posted it.
>
> http://rosettacode.org/wiki/Atomic_updates#D
>
> I incorporated some of your and monarch_dodra's suggestions.

Just curious: in the transfer function, why do you lock/unlock 
the lower bucket number first? Why does the order matter?