ICallbackEventHandler changes in July CTP

Prior to the July CTP of VS 2005, the ICallbackEventHandler had just one method with the following signature:

string RaiseCallbackEvent (string eventArgument)

The eventArgument was the string that came from the client and the return string went back to the client.

In July CTP, the ASP.Net team split up the processing into two calls that now make up the ICallbackEventHandler:

void PrepareCallbackEvent (string eventArgument)
string RenderCallbackResult ()

The idea remains the same, you process the incoming data in PrepareCallbackEvent and put together the return payload in RenderCallbackResult.