(Copy'n'paste of reddit comment:) While it's true that the Windows API seems to be the best thought through, I was surprised to learn that the implementation m

(Copy'n'paste of reddit comment:) While it's true that the Windows API seems to be the best thought through, I was surprised to learn that the implementation may randomly fall back to synchronous IO in unpredictable ways, which (depending on the app, but likely for something that's attempting to juggle a lot of work like a bittorrent implementation) means you need a thread pool anyway. http://neugierig.org/software/blog/2011/12/nonblocking-disk-io.html http://neugierig.org/software/blog/2011/12/nonblocking-disk-...