Two coverage facts are knowable before any lookup and are reported as such: a
zoom outside the region's own minZoom/maxZoom, and — when the region's CRS
is provably WGS84 lon/lat — a tile whose envelope does not meet the region's
bounds. Both are out-of-region, which is a truer answer than the cache miss
that would otherwise follow, and neither touches storage.
Read one tile from a persisted region.
Two coverage facts are knowable before any lookup and are reported as such: a zoom outside the region's own
minZoom/maxZoom, and — when the region's CRS is provably WGS84 lon/lat — a tile whose envelope does not meet the region's bounds. Both areout-of-region, which is a truer answer than the cache miss that would otherwise follow, and neither touches storage.