pub fn take_due_digest(root: &Path) -> Option<ImpactDigest>Expand description
Return the periodic value digest when it is due, stamping the store so the
next one is at least DIGEST_INTERVAL_SECS away. Due means: tracking is
enabled, there is non-zero value to report (anti-nag: a zero digest never
surfaces), and the previous digest is older than the interval (or never
happened). Best-effort like the rest of the store: a clean run that drops
the emitted step simply defers the digest to the next interval.