How to get s3 upload progress about amazon-cognito-identity-dart-2 HOT 7 CLOSED

    final dio.FormData formData = dio.FormData.fromMap({
      'key':policy.key,
      'X-Amz-Credential': policy.credential,
      'X-Amz-Algorithm': 'AWS4-HMAC-SHA256',
      'X-Amz-Date': policy.datetime,
      'Policy': policy.encode(),
      'X-Amz-Signature': signature,
      'x-amz-security-token': _credentials.sessionToken,
      'file': await dio.MultipartFile.fromFile(
        file.path,
        filename: fileName,
      )
    });

    try {
      await dioObj.postUri(
        uri,
        data: formData,
        onSendProgress: (int sentBytes, int totalBytes) {
          double progressPercent = sentBytes / totalBytes * 100;
          print("$progressPercent %");
          eventBusAwsUpload.fire(BSAwsUploadEvent(fileName,progressPercent));
        },
      );

    } catch (e) {
      print("uploadS3 error> "+e.toString());
    }

        final res = await req.send();
        await for (var value in res.stream.transform(utf8.decoder)) {
          print('UploadS3 success $value');
        }

await req.send().then((result) async {
        http.Response.fromStream(result)
            .then((response) {

          print("uploadS3_1> "+utf8.decode(response.bodyBytes).toString());
          return response.body;

        });
      }).catchError((err) => print('error : '+err.toString()))
          .whenComplete(()
      {});

final req = http.MultipartRequest("POST", uri);
    final multipartFile = http.MultipartFile('file', stream, length,
        filename: path.basename(file.path));

    final String fileName = path.basename(file.path);
    final String usrIdentityId = _credentials.userIdentityId;
    final String bucketKey = '${keyResolver.user_email}/$fileName';

    final policy = Policy.fromS3PresignedPost(
        bucketKey,
        'files',
        15,
        _credentials.accessKeyId,
        length,
        _credentials.sessionToken,
        region: backendConstants.aws_region);
    final key = SigV4.calculateSigningKey(
        _credentials.secretAccessKey, policy.datetime, backendConstants.aws_region, 's3');
    final signature = SigV4.calculateSignature(key, policy.encode());

    req.files.add(multipartFile);
    req.fields['key'] = policy.key;
    //req.fields['acl'] = 'public-read'; // Safe to remove this if your bucket has no ACL permissions
    req.fields['X-Amz-Credential'] = policy.credential;
    req.fields['X-Amz-Algorithm'] = 'AWS4-HMAC-SHA256';
    req.fields['X-Amz-Date'] = policy.datetime;
    req.fields['Policy'] = policy.encode();
    req.fields['X-Amz-Signature'] = signature;
    req.fields['x-amz-security-token'] = _credentials.sessionToken;

response.progress.listen((int progress) {
      print("progress from response object " + progress.toString());
    });