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# findUnusedTrackID(completionHandler:)

Loads an identifier that no other track in the asset uses.

```
func findUnusedTrackID(completionHandler: @escaping @Sendable (CMPersistentTrackID, (any Error)?) -> Void)
```

## Parameters

`completionHandler`

A completion handler the system calls after it finishes the request.

## Discussion

---

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