Function spawn_blocking 

pub fn spawn_blocking<T>(
    f: impl FnOnce() -> T + Send + 'static,
) -> Task<Result<T, Box<dyn Any + Send>>> 
where
    T: Send + 'static,

Available on crate feature runtime only.

Spawns a blocking task in a new thread, and wait for it.

The task will not be cancelled even if the future is dropped.

Panics

This method doesn’t create runtime. It tries to obtain the current runtime by Runtime::with_current.