NIO: improvements to Windows BSD API (#1659)
NIO: improvements to Windows BSD API (#1659)

Some improvements to the API surface to actually handle some more error
cases correctly and fix typing.

Co-authored-by: Cory Benfield <e2b4f0650e369574e9b0029c3b3893634b6d4097@apple.com>
apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio