I focused on an object in the house. With the toggle set to the circle, I could shoot quite a few shots, including refocus.
I noted the image number on the LCD. 168
When I had the inline switch in the hyphen position, I shot 18-20 RAW images before it filled the buffer and started slowing down. I waited several minutes to switch from the hyphen position to the circle. Sure enough, none of the new images had been moved from the buffer to the card. It read 168, but started increasing as it added the next 20 new images.
If you have additional insights, I'd love to hear them.