[Issue 21560] md5 poor performance out of the box

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21560

--- Comment #6 from Chloé <chloekek at use.startmail.com> ---
Since you have 128 GB memory you could load the entire file into a byte array
and compute the hash from there. Start the timer after loading the entire file.
This should eliminate any potential difference in I/O from the tests. Of
course, you will need to do the same with md5sum and OpenSSL.

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