Function start_with_service 

pub async fn start_with_service(
    app_state: GenericServerState,
    app_config: &impl GenericSetup,
    service: Service,
) -> MResult<(Pin<Box<dyn Future<Output = ()> + Send>>, ServerHandle)>

Starts your application with provided service, if you predefined one by yourself.

For example, you can setup service with error catcher or any other middleware that salvo provides.