Cliffhangers in coding

So what am I reading? Well, come back later, I can tell you what it’s about. That sounds quite async when you have to await.
LAst year I implemented a migrationscript. After some optimizations it ran 4 hours, and the only feedback was the indication on top of the browser-tab, while the browserpage itself was empty and waiting. If I implemented this solution, it would be a nicer UX…