Low write performance on Windows

[akrylysov]

More details at #22.

Key size=16, value size=1.

Writing 1M items on Linux - 16 sec.
Writing 1M items on Mac - 14 sec.
Writing 1M items on Windows - 165 sec.

[cocowalla]

Just found pogreb through your original blog post, and looking through the repo came across this issue.

It might not be your issue, but I recall seeing worse performancebon Windows last time I used memory mapped files for something, even though performance was much better in Linux. That was with dotnet rather than Go, and of course it's perfectly possible I simply messed something up, but a quick Google search does seem to find others saying the same thing 🤷‍♂️