public AzureStorageBlobAttachment(string identifier, IMessage message, FileReference fileReference, AzureStorageBlobReference blobReference)
     : base(identifier, message)
 {
     this.fileReference = fileReference;
     this.blobReference = blobReference;
 }
 public AzureStorageBlobAttachment(string identifier, IMessage message, FileReference fileReference)
     : this(identifier, message, fileReference, null)
 {
 }