While quoting me you omitted the phrase “by default”. I said “When it comes to performance, rust+tokio is going to be much more performant by default”.
What I meant was in the typical case, you can expect rust+tokio to be faster than Haskell. This is not a surprise as rust is much more low level, does not have a GC and its compiled output maps better to modern processors rather than the pure functional lazy style of Haskell.
Plenty of benchmarks across a variety of workloads and program confirm that Haskell is slower than rust on average. For webserver type use cases (which uses a lot of Async) Rust is faster. Check out tech empower benchmarks for example.
This is nonsense without significant further qualification.
I guarantee the tokio scheduler and async stack model gives you net worse results for many real workloads.