>My understanding of IOCP is that the model requires the following: if you want to, say, receive data on a socket, you supply the IOCP w/ a buffer/length. After some data has been received, the buffer and the amount received are returned to you.

And then you have a language with GC and you want a async IO, and your runtime becomes so messy with IOCP support, so you just use poll on windows, as many languages do. kqueue is fine, but messy and incomprehensible, and I don't see how is it fundamentally better than epoll with ET.