Jason is working on it right now. He had to pause for a while as we get ready for release, so it won't be added pre-release. However, it's still a priority.
Thank you thank you thank you! As one of the people with terrible connections this will save me so much grief in the long run.
As Jon said - it's one of my top post-release priorities. For a little behind-the-scenes view: support for reconnecting to a game in progress is what brought us spectator mode, since re-establishing game state was a first step in getting a player back into their game.
