Function futures_ext::asynchronize

pub fn asynchronize<Func, T, E>(f: Func) -> impl Future<Item = T, Error = E> where
    Func: FnMut() -> Result<T, E> + Send + 'static,
    T: Send + 'static,
    E: From<BlockingError> + From<Canceled> + Send + 'static, 

This method allows us to take synchronous code, schedule it on the default tokio thread pool and convert it to the future. It's the combination of spawn_future (which runs a future on another thread) and closure_to_blocking_future (which turns a closure into a future).