Function serve_here_with_upgrades 

pub async fn serve_here_with_upgrades<F>(
    addr: &str,
    handler: F,
    upgrades: Vec<(&str, UpgradeHandler)>,
) -> Result<()>
where
    F: FnMut(HttpRequest) -> HttpResponse,

serve_here with a table of protocol-upgrade paths, as serve_with_upgrades.