Victor, I addressed the majority of your comments except for a couple stylistic pieces. Your annoyance with the short poll time for Windows made me re-read the docs from MS, which made me realize that my interpretation was wrong. It also made me confirm Richard Oudkerk's earlier note about ReadFile on overlapped IOs.

I left similar notes next to your comments.

On the method naming side of things, note that you can only write to "stdin", and you can only read from "stdout" or "stderr". This is documented behavior, so I believe the method names are already quite reasonable (and BDFL approved ;)).