To complete my unintentional series on EWS notifications, I have written a sample application showing how to deal with streaming subscriptions. The application includes full logging of both events and EWS calls, so is very useful for troubleshooting. The screenshot below shows the application in action.
Streaming notifications are fully implemented in the EWS Managed API, so implementing them in an application is fairly straight-forward. The StreamingSubscriptionConnection class raises events, so all you need to do is respond to these events accordingly. Most of the other code is the same as in the other notification samples (action on the events is performed on new threads, and this application simply reads some more information about the item).
Please note that the application is no longer available for download from this page, please go to Codeplex where you can download source and the binary: https://ewsstreaming.codeplex.com/