#[tokio::main]
async fn main() {
    let cors = warp::cors()
        .allow_any_origin()
        .allow_header("not-in-the-request")
        .allow_methods(
            &[Method::PUT, Method::DELETE, Method::GET, Method::POST]
        );
    ...
    let get_items = warp::get()
        .and(warp::path("questions"))
        .and(warp::path::end())
        .and_then(get_questions);
    let routes = get_items.with(cors).recover(return_error);
}