Write queue after connect windows

I think  we need a better approach here. I'd say that we should return EPIPE if closing / closed and EINVAL if we are not trying to connect. "Trying to connect" would be when stream->connect_req is not NULL. We need to add that field on Windows, I think it makes things easier. Unix would also need adjusting. This is more strict, yes, but more correct and easier to reason about IMHO.