if err != nil {
		b.Fatal(err)
	}

	// Insert objects to be listed and benchmarked later.
	for i := 0; i < 20000; i++ {
		key := "obj" + strconv.Itoa(i)
		_, err = obj.PutObject(context.Background(), bucket, key, mustGetPutObjReader(b, bytes.NewBufferString(key), int64(len(key)), "", ""), ObjectOptions{})
		if err != nil {
			b.Fatal(err)
		}
	}