public class BlobUploadModel
{
    public string FileName { get; set; }
    public string FileUrl { get; set; }
    public long FileSizeInBytes { get; set; }
    public long FileSizeInKb { get { return (long)Math.Ceiling((double)FileSizeInBytes / 1024); } }
}

public class BlobDownloadModel
{
    public MemoryStream BlobStream { get; set; }
    public string BlobFileName { get; set; }
    public string BlobContentType { get; set; }
    public long BlobLength { get; set; }
}