Function spawn_rayon 

pub fn spawn_rayon<Output: Send + Sync + 'static, F: FnOnce() -> Output + UnwindSafe + Send + 'static>(
    f: F,
) -> ClosureFuture<Output> 

Available on crate feature rayon only.

An helper function to spawn a closure on the rayon global threadpool. Requires feature “rayon” to be activated.