It's exciting to see another thread-per-core async runtime for Rust. It's truly understated how difficult the Send + Sync requirements in Tokio are for writing regular code. It's typically rare for async tasks in Tokio to be used across two threads simultaneously, but now all of your data must be Send+Sync.
Plus, Tokio is unique in that it's one of the very few runtimes in existence that's work-stealing (meaning the task can move off its original thread). Most other runtimes in other languages do not have that requirement, meaning you can use traditional Cell/RefCell/Rc instead of their slower, atomic variants.
Right now, the best you can do is write a thread pool that spawns a Tokio LocalSet to run !Send futures. In fact, this is what Actin-web does to achieve its crazy performance. Web requests finish so quickly you rarely need work-stealing to achieve good performance, and often the cost of atomics/stealing is greater than the performance gain.
Plus, Tokio is unique in that it's one of the very few runtimes in existence that's work-stealing (meaning the task can move off its original thread). Most other runtimes in other languages do not have that requirement, meaning you can use traditional Cell/RefCell/Rc instead of their slower, atomic variants.
Right now, the best you can do is write a thread pool that spawns a Tokio LocalSet to run !Send futures. In fact, this is what Actin-web does to achieve its crazy performance. Web requests finish so quickly you rarely need work-stealing to achieve good performance, and often the cost of atomics/stealing is greater than the performance gain.