I wrote myself a debug tool at 2007. It's a piece of GUI "to borrow". A Windows app that catches Windows messages addressed to it and shows things in its own windows. It can show numbers you give it, give numbers back, count calls, and measure time. So it's a kind of debugger/profiler/GUI.

I open sourced it 8 years ago but it was not the original intention. I wrote it for myself. https://github.com/akalenuk/16counters

I wrote it in MASM32. It's therefore a tiny .exe file of about 7 KB. I spent maybe a few hours initially, but I've been adding features one-by-one for several years. I use it a few times a month.