The result of Dust.single_flight/4.
value— the materialized result (same shape regardless ofsource).source— provenance::cached(fresh local hit, no work),:computed(this caller ranfun), or:awaited(another filler ran it; this caller rode the result).stale?—trueonly when a freshness-mode wait timed out and the last known (stale) value is returned rather than a fresh one.coordinated?—falseonly on the degradedon_unavailable: :run_localpath, wherefunran without a lease (possible duplicate work). This is the one signal that idempotency actually mattered on this call.