onchangeevent handler of the
DataStoreinterface fires when a change is made to the data store. Its main use is to synchronize different apps that are using the data store when a change is made. When fired, this event returns a
DataStoreChangeEvent, which can be used to handle the change that was just made. Alternatively, when the event fires you could create a
DataStoreCursorand iterate through all the records, if needed.