It is useful for application developers to know when a particular class has completed a transaction it was meant to do.
Example, my app may want to know when EventRecorder has finished completing an event recording to update my DB, or when MovieFileOutput writes a video.
It is useful for application developers to know when a particular class has completed a transaction it was meant to do.
Example, my app may want to know when EventRecorder has finished completing an event recording to update my DB, or when MovieFileOutput writes a video.