When will be available a method to reboot [or shutdown] the guest from the API?

Hello,

as many others before I need to have a method to reboot or shutdown the guest from the API. There are alternatives but all of them have some rougth edges that cannot be avoided so would be much better to have a method from the API.

I've seen that at 2008 this was planned to be implemented. What has happened with it? Will it be implemented in any version?

Thanks for your answers.