4 ms·It can also be done with a bit of cardboard that says “Busy”.by caseyy 1y agoIt can also be done with a bit of cardboard that says “Busy”.zhovner 1y agoCardboard sign has no countdown timer and API.caseyy 1y agoThat's true. And it doesn't even have a display on the other side — how will you yourself know if you're busy?