Function sweep_after 

pub fn sweep_after(
    folder: &Path,
    mine: &mut BTreeMap<String, i64>,
    used: &BTreeSet<String>,
    now_ms: i64,
    days: i64,
)

As sweep, after days unused: UNUSED_DAYS, or UNUSED_DAYS_BEFORE while a device of the sharing runs an older Sioul (share::unused_days).