Portable Async Programming in D2

[eris0xff]

I've been away from D for a while.  While I do have Andrei's 
book, most of my experience has been with D1 and generally very 
positive.

Anyway, I've been doing a fair amount of async, callback-oriented 
network programming using libuv in C in my curent project.  I'd 
like to implement my next version of the project in D version 2.

I don't want to use libuv if there are portable, reliable and 
built-in D mechanisms to:

1. Manage multi-threaded, message passing, event-oriented 
callback loops.
2. Portable task/thread pools with priority.
3. Transparent select/epoll implementation on POSIX and IO 
Completion on Windows.

I'm know that threading and task pools are available and I think 
(perhaps) the message send functionality has a priority send.

The transparent event-oriented async I/O is where I get a little 
fuzzy in the std/core libraries.  I have very little information 
on how async I/O is implemented (if at all) in D standard 
libraries, especially whether it uses IO completion on Windows.

Please excuse if this isn't completely clear, I'm still working 
on 1st cup of coffee.

thx

eris0xff