Function file_append_log_default 

pub fn file_append_log_default<T>(
    dir: impl AsRef<Path>,
) -> AppendLogStorage<FileBackend, T, JsonCodec>
where
    T: Serialize + DeserializeOwned + Clone + Send + Sync + 'static,

Convenience: append-log tier over a fresh file backend with AppendLogStorageOptions::default + a JsonCodec.