Function handler

http/src/util/service/handler.rs:354–368

(
        method: &Method,
        addr: &SocketAddr,
        uri: &Uri,
        headers: &HeaderMap,
        (_, ext): (&Request<RequestExt<()>>, &Extensions),
    )

    use super::*;

    async fn handler(
        method: &Method,
        addr: &SocketAddr,
        uri: &Uri,
        headers: &HeaderMap,
        (_, ext): (&Request<RequestExt<()>>, &Extensions),
    ) -> StatusCode {
        assert_eq!(method, Method::GET);
        assert_eq!(*addr, unspecified_socket_addr());
        assert_eq!(uri.path(), "/");
        assert!(headers.is_empty());
        assert!(ext.is_empty());

        StatusCode::MULTI_STATUS
    }

    impl Responder<Request<RequestExt<()>>> for StatusCode {
        type Response = Response<()>;