timelessnesses/human-latency ? reverse-engineered prompt

Build me a small desktop app that tests human reaction time, kind of like the Human Benchmark reaction test.

I want a simple full screen or windowed game where the screen changes, I click or press a key as fast as I can, and it shows my reaction time in milliseconds. It should feel snappy and use SDL2, with very smooth timing and a clean minimal interface. After each round it should let me try again easily and maybe show my best time or a few recent results. If I click too early, it should tell me I was too fast and restart the round. Keep the whole thing lightweight and make it work as a normal Rust app I can build and run locally.

If you need to, look up current docs online, but keep the implementation simple and focused on getting the reaction test working well.