Function save

pub fn save<W, E, F>(
    cookie_store: &CookieStore,
    writer: &mut W,
    cookies_to_string: F,
) -> Result<(), Error>
where
    W: Write,
    F: Fn(&Vec<Cookie<'static>>) -> Result<String, E>,
    Error: From<E>,

Serialize any unexpired and persistent cookies in the store with cookie_to_string and write them to writer