pub fn ls(cache: &Path) -> impl Iterator {
    let mut path = PathBuf::new();
    path.push(cache);
    path.push(format!("indev-v{}", INDEX_VERSION));
    WalkDir::new(path).into_iter().flat_map(|bucket| -> Result<_, Error> {
        let bucket = bucket?;
        let entries = bucket_entries(bucket.path())?;
        let mut dedupe: HashMap<String, SerializableEntry> = HashMap::new();
        for entry in entries {
            dedupe.insert(entry.key.clone(), entry);
        }
        Ok(dedupe
            .into_iter()
            .filter(|se| se.1.integrity.is_some())
            .map(|se| {
                let se = se.1;
                Entry {
                    key: se.key,
                    integrity: se.integrity.unwrap().parse().unwrap(),
                    time: se.time,
                    size: se.size,
                    metadata: se.metadata,
                }
            })
        )
    })
}

// let entries: Result<Vec<_>, _> = ls(&dir);