Function save_to_file

pub fn save_to_file<D, F, T, G>(
    in_stream: &Stream<G, D>,
    filename: &str,
    format: F,
) -> Stream<G, D>
where
    D: Data,
    F: Fn(&D) -> String + 'static,
    T: Timestamp,
    G: Scope<Timestamp = T>,