The minimum delay a delay change sets; null on an upgrade.
Upgrades execute on the sweep's next run once ready. Delay changes never do.
False at a zero delay: there is no window in which to review it.
The timelock's minimum delay.
When it becomes ready; null while UNSENT.
The release an upgrade moves to; null on a delay change.
UNSENT: stored, not yet on chain. WAITING: on chain, delay running. READY: delay over.
The sweep's execute row for a ready upgrade, once it is dead. The one state that
offers Retry: a runtime mismatch, a stuck schedule row and a delay change stay null.
One timelock operation still in flight, from its stored schedule row.