Thanks, this was a fun experiment. I was curious to see what language you used. I've done a bit of scala many years ago, and I have to say that I HATED other peoples weird and often over complex scala code. I think this is the main difference in our point of view. I 100% agree that you can write better abstractions with a language like Scala, but you can also shoot yourself in the foot far far easier. If you have a small team of very talented devs, something like scala can be amazing. At a large company, with thousands of developers of varying levels, I find you get worse results with something like scala relative to Go.
I also think that a dev who just graduated college would be able to jump into my code and work on it fairly easily. I think they'd need a lot of extra training/learning to understand yours.
One question about yours, is it using a separate OS thread for each HTTP call, or some kind of async io?