FPS offers an event notification mechanism that allows your application to receive notification messages directly from FPS when something of interest occurs in the service. The service sends the notifications as SOAP messages to your application, which can interpret and act on the information in the message. You can register for two kinds of event notifications.
When your application performs an asynchronous transaction operation that cannot be completed immediately, FPS sends a response message indicating that the transaction has been initiated. By default, is the responsibility of your application to use the GetResults operation to poll FPS for status updates to find out when the transaction is completed. This polling approach is described in Handling Transaction Results” in Chapter 11.
If you register for transaction result notifications, FPS will contact your application directly to notify it when the status of your transaction changes. This means that your application will no longer be obliged to poll the service for transaction status updates; instead, it can sit back and wait for the event notification messages to arrive from FPS.
You must choose between monitoring transaction status changes through notifications or through polling: you cannot do both. If you subscribe to receive transaction result notification messages, the GetResults operation will no longer return transaction results.
The third-party ...