Function spawn_local 

pub fn spawn_local<F>(future: F) -> JoinHandle<F::Output>
where
    F: Future + Send + 'static,
    F::Output: Send + 'static,

Spawn this future on this local thread runtime.

You should generally replace your tokio::spawn with this. By using spawn_local instead of tokio::spawn, you give the load heuristic more information.

If your work truly does not have a thread affinity consideration, use spawn_balanced instead.