rows

type TelemetryCallbacks struct {
	// OnChunkFetched is called after each result page fetch with chunk-level stats.
	OnChunkFetched func(chunkCount int, bytesDownloaded int64, chunkIndex int, chunkLatencyMs int64, totalChunksPresent int32)
	// OnClose is called from rows.Close() after all rows have been consumed.
	// iterErr is the first error from Next()/fetchResultPage (nil if iteration succeeded).
	// closeErr is the error from the CloseOperation RPC (nil if close succeeded).
	OnClose func(latencyMs int64, chunkCount int, iterErr error, closeErr error)
	// OnCloudFetchFile is called per S3 file download for CloudFetch result sets.
	OnCloudFetchFile func(downloadMs int64)
}