fix 'parameter incorrect' issue when using unbuffered IO on windows
fix 'parameter incorrect' issue when using unbuffered IO on windows

aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent,aindigo/rasterbar_libtorrent