libgit2 status

What is the status of libgit2 WRT the overall git project? I recall that there was some discussion of basing bits of git on libgit2 once it matures.

I ask because I'm starting a project to improve the abysmal speed of git-subtree split. It's unbearably slow at the moment and as far as I can puzzle out it's due almost entirely to repeated subshell invocations to run git commands.

I was planning on doing some experiments rewriting bits of git-subtree using libgit2 but I want to make sure that that isn't wasted work. It appears to be exactly what I need to code bits of git-subtree natively.

Thoughts?

                        -Dave