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# CKSyncEngineWillFetchChangesEvent

The sync engine is about to fetch changes from the server.

```
@interface CKSyncEngineWillFetchChangesEvent : CKSyncEngineEvent
```

## Overview

The sync engine delivers the changes themselves via [`CKSyncEngineFetchedDatabaseChangesEvent`](/documentation/CloudKit/CKSyncEngineFetchedDatabaseChangesEvent) and [`CKSyncEngineFetchedRecordZoneChangesEvent`](/documentation/CloudKit/CKSyncEngineFetchedRecordZoneChangesEvent).

Note that this event might not always occur every time you call [`fetchChangesWithCompletionHandler:`](/documentation/CloudKit/CKSyncEngine-4b4w9/fetchChangesWithCompletionHandler:).
For example, if you call [`fetchChangesWithCompletionHandler:`](/documentation/CloudKit/CKSyncEngine-4b4w9/fetchChangesWithCompletionHandler:) concurrently while the engine is already fetching changes, this event might not be sent.
Similarly, if there’s no logged-in account, the engine might short-circuit the call to `fetchChanges`, and this event won’t be sent.

---

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