bulk
suspend fun bulkFetchTile(z: Int, x: Int, y: Int, sector: Sector, overrideCache: Boolean = false): Flow<CachedFeatureRow>?
Bulk-download counterpart to fetchTile — used by "save a region for offline use" flows. Ignores isCacheOnly (bulk always allows network) and writes the FULL fetch through to store. The write-through happens when the returned flow is collected, so the caller must drain it. Returns null when there's nothing to fetch (no rows / no network source).
Unlike fetchTile, transport errors are NOT swallowed to null: they surface during collection so the bulk-retrieval loop can retry with backoff instead of recording a permanent miss.
Parameters
override
when true, re-fetch from the network even if the tile is cached.