in 2016 Casey Muratori wrote a few words about his old video "IMMEDIATE-MODE GRAPHICAL USER INTERFACES (2005)" -- apparently he'd been using the technique for years by then and had coined the, now commonly used, imgui acronym -- see: https://caseymuratori.com/blog_0001

and if you dive into that video at 16:50 you'll see a very elegant description of minimal state immediate mode button logic; direct time link: https://youtu.be/Z1qyvQsjK5Y&t=16m50s