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# setUserCallback(_:)

Adds a callback that the sequencer calls each time it encounters a user event during playback.

```
func setUserCallback(_ userCallback: AVAudioSequencerUserCallback?)
```

## Parameters

`userCallback`

The user callback that the system calls.

## Discussion

The system calls the same callback for events that occur on any track in the sequencer. Set the callback to `nil` to disable it.

---

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