The callback model for processing event types allows your client application to register one or more callback functions to process event types for a Broker client.Unlike the get-events model, which can only process event types for one Broker client at a time, the callback model can receive any event type for any of your client application's Broker clients and then dispatch it to the appropriate callback function. If your client application creates several Broker clients, using the callback model frees your application from making separate calls to one of the webMethods Broker get-event functions for each Broker client.