title: Doing a conditional update in dynamodb with the data model
body: <p>Is it possible to do a conditional update of an item in dynamodb using the data model as you can with the <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LowLevelDotNetItemsExample.html" rel="nofollow">document model</a>?  If there isn't a way to do a conditional update does the .Net SDK have a method to convert an object into an UpdateItemRequest object?</p>