I'm confused by the documentation and the examples. The documentation suggests there is a getDataItem function but I can't find a concrete API documentation or sample code that uses it. The examples use sendMessage on the client which is received as a notifyUser on the server, but I can't find documentation that describes that mapping. I think I want to use getDataItem to request asynchronous data from the server but I can't figure out how to do it. Does anybody have any specific examples of a client requesting one-shot data, and the server responding directly to a single user once?