What languages are you interested in?
There's not a tracking issue to my knowledge, but there is a
merged implementation for Java. It'll be in the next release, which is about two weeks away. Please feel free to try it out from master or the freshly-cut v1.3 branch. If you notice any problems, there's time to fix it before the release.
If you're interested in other languages, I think they are on the same approximate timeline, but I've not been tracking their status. They may not make 1.3, but I'd be surprised if the feature was still missing in 1.4.