See if the task execution engine can be single-threaded

[GWBasic]

When using async code in rust, there are a lot of idle threads.

See if the async engine can be configured to be single-threaded; or follow a thread-per-core model.

[GWBasic]

I briefly looked into this. I suspect it requires replacing task::spawn and using platform-specific code to block while waiting for IO. Alternatively, it may require using task::spawn_local once it's part of stable rust: https://docs.rs/async-std/1.7.0/async_std/task/fn.spawn_local.html

At this point, I'll keep the ticket open