public string CompletePartToCloud()
    {
        // Step 3: complete.
        CompleteMultipartUploadRequest compRequest = new CompleteMultipartUploadRequest();

        compRequest.BucketName = this.DestinationBucket;
        compRequest.Key        = this.DestinationFilename;
        compRequest.UploadId   = initResponse.UploadId;
        compRequest.PartETags  = uploadPartETags;
        string r = "Something went badly wrong";

        using (CompleteMultipartUploadResponse completeUploadResponse = client.CompleteMultipartUpload(compRequest))
            r = completeUploadResponse.ResponseXml;
        return(r);
    }