Kink made some modifications to their cassette driver to turn it into a freecoaster driver. The idea is simple, they added a retention ring and coaster pawls as you can see in the technical drawing. Furthermore you can get an 8T driver which noone else offers as far as we know. The best thing tho is that they are selling this system seperately as a modification/upgrade kit for their hubs.
A few more words from the Kink website: "Probably the biggest advantage to the Kink freecoaster system; it’s a simple upgrade to the existing Kink Incite cassette hub and all future Kink cassette hubs. Simply purchase a few parts to upgrade your driver to a freecoaster. Another advantage is that you can have an 8T (or 9T) freecoaster, which doesn’t currently exist on the market. Of course if you aren’t feeling the freecoaster, you can easily switch it back to a cassette."