log.trace(String.format("Checksum data %s type %d signature %s", Hexdump.toHexString(checksumData),
                    this.serverSignature.getType(), Hexdump.toHexString(this.serverSignature.getChecksum())));
        }

        byte checksum[] = PacMac.calculateMac(this.serverSignature.getType(), keys, checksumData);
        if (!MessageDigest.isEqual(this.serverSignature.getChecksum(), checksum)) {

			headers:            map[string]string{"x-amz-checksum-crc32": checksumData(bytesData, crc32.New(crc32.IEEETable))},
			data:               bytesData,
			dataLen:            len(bytesData),
			accessKey:          credentials.AccessKey,
			secretKey:          credentials.SecretKey,
			expectedRespStatus: http.StatusOK,
			wantHeaders:        map[string]string{"x-amz-checksum-crc32": checksumData(bytesData, crc32.New(crc32.IEEETable))},
		},