Add a new status to posts

In addition to Published and Draft it would be nice to have another status option for posts. The new status could be Unpublished. In an environment where multiple people are working on posts collaboratively, it is helpful to know what is in a finished but unpublished state and what is a work in progress.

Published = available to read on the site
Unpublished = content is in final state but has not been made available to read on site
Draft = content is still in a working state and post is not available to read on site.

Thanks for your consideration.