[boost] [asio] Feature request: console IO

Hello everyone, here is a greeting for joining the list. I want to request console support in asio. Some reasons: 1. non-block stdin is useful for some applications. 2. Linux can do non-block IO on ttys. Implementation concept: 1. Linux: if using epoll, first check if target is a regular file. If not, fall back to threaded non-blocking IO. select(), poll() can be use on any valid fds. 2. Windows: this garbage doesn't support overlapped console IO. Create a separate thread for std{in,out,err}, then communicate with the thread. 3. Other *nix: I don't know. It could already be used through POSIX stream descriptor, but it is too limited and platform specific. A library can cover these gaps is great. I hope you like this idea.