Also worth noting that the 10x improvement is for tokio's own benchmarks, and even there only in one of the four. The hyper benchmark saw "only" a 34% improvement.
There were no unchecked facts in the original post. It is a fact that I have got 100x speedups, and it is my personal experience that 10x speedups rarely come close to exhausting the opportunities.
It is a fact that I did not notice any reference in the article to GCD or the techniques that have made it a success.
Hint: tokio based web servers are the fastest.