Lock assets when they're being edited

I don't know if this already exists, but in enterprise situations it's not uncommon for several people to get a request to update an asset or workflow simultaneously. To alert a user that someone is actively editing an asset, it would be nice to see a lock symbol on the icon (similar to the + now when the asset is in draft mode) and forbid users from creating an additional draft mode. Multiple users aren't the only problem here, sometimes having an asset open in two windows can cause good work to go away if you select the wrong window.