impl<ReqBody, ResBody, S, Store: SessionStore, C: CookieController> Service<Request<ReqBody>>
    for SessionManager<S, Store, C>
where
    S: Service<Request<ReqBody>, Response = Response<ResBody>> + Clone + Send + 'static,
    S::Future: Send,
    ReqBody: Send + 'static,
    ResBody: Default + Send,
{
    type Response = S::Response;
    type Error = S::Error;
    type Future = impl Future<Output = Result<Self::Response, Self::Error>> + Send; //<- Modified here
    ...
    fn call(&mut self, mut req: Request<ReqBody>) -> Self::Future {
        ...
         //<- No more Box::Pin here
        async move {
           ...
       }
    }
}