Function response_warning_code

http-cache/src/lib.rs:1987–1993

Extracts the warning code from an `http::Response`'s warning header, if present. Returns the 3-digit warn-code as a `usize`.

(response: &Response<B>)

    /// By default, a manager implementation with [`cacache`](https://github.com/zkat/cacache-rs)
    /// as the backend has been provided, see [`CACacheManager`].
    pub manager: T,
    /// Override the default cache options.
    pub options: HttpCacheOptions,
}

/// Wrapper for user metadata stored in response extensions during cache reads.
/// Used to preserve metadata through 304 re-cache operations so that
/// `StreamingCacheManager::put` receives the original metadata instead of
/// regenerating it (which may produce different or empty results).
#[derive(Debug, Clone)]