Function run_blocking 

pub async fn run_blocking<Fn, T, E>(f: Fn) -> Result<T, E>
where
    Fn: FnOnce() -> Result<T, E> + Send + 'static,
    T: Send + 'static,
    E: From<JoinError> + Send + 'static,

Runs a blocking function in a worker thread.

This function preserves the tracing span.