debugIndexInParentIterationCount property
Debug-only: cumulative count of sibling-probe loop iterations performed by the live-index cache refresh that backs getIndexInParent. Counts iterations rather than calls so tests can pin exact budgets: a cache-hit read costs ZERO iterations, and a refresh costs the touched list's FULL raw length (it rebuilds every live member's slot, not just the probed key's prefix). Never reset internally; tests zero it directly.
Implementation
int debugIndexInParentIterationCount = 0;