While impressive, that is a project that is basically perfectly suited to gain the most from this kind of optimization, and the fact that it already was incredibly fast means that there are fewer low hanging fruits for performance, and other projects would be less likely to have as big wins (as they're more likely to already have bigger bottlenecks elsewhere).

That’s really promising! uSockets/uWebSockets is an almost perfect use case for io_uring. That library is also insanely performant and well written. I ran some benchmarks mostly for low memory overhead and it’s much better than even Go std, nginx+nchan etc etc.