diff --git a/internal/s3/client.go b/internal/s3/client.go
index 3d7481d..346d325 100644
--- a/internal/s3/client.go
+++ b/internal/s3/client.go
@@ -11,6 +11,7 @@ import (
 	"git.frostfs.info/TrueCloudLab/xk6-frostfs/internal/stats"
 	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
+	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
 	"github.com/aws/aws-sdk-go-v2/service/s3/types"
 	"github.com/dop251/goja"
 	"go.k6.io/k6/js/modules"
@@ -88,6 +89,7 @@ func (c *Client) Multipart(bucket, key string, objPartSize int, payload goja.Arr
 		stats.Report(c.vu, objPutFails, 1)
 		return PutResponse{Success: false, Error: err.Error()}
 	}
+	sz := len(data)
 	stats.Report(c.vu, objPutTotal, 1)
 	stats.ReportDataSent(c.vu, float64(sz))
 	stats.Report(c.vu, objPutDuration, metrics.D(time.Since(start)))