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Summary:
I made a simple example with a UICollectionView and prefetching activated. I put some logs and you can see that always on prefetching cellForAtIndexPath is called. Is that guaranteed? It is always the case except for on item 0

Steps to Reproduce:
1. Run sample
2. Look at the ouput in Xcode

2016-10-04 08:11:12.668 PrefetchingSample[94247:11189819] Cell for row at indexPath: [0, 0]
2016-10-04 08:11:12.689 PrefetchingSample[94247:11189819] Prefetching indexPath: [[0, 1]]

3. Scroll to page 1

2016-10-04 08:11:43.956 PrefetchingSample[94247:11189819] Cell for row at indexPath: [0, 1]
2016-10-04 08:11:44.134 PrefetchingSample[94247:11189819] Prefetching indexPath: [[0, 2]]
2016-10-04 08:11:44.190 PrefetchingSample[94247:11189819] Cell for row at indexPath: [0, 2]

Now you see that a prefetching also calls cellForItemAtIndexPath.

So my question is: Is that desired behavior or can this change in the future 
or is guaranteed that cellForItemAtIndexPath is called after prefetching method?

Expected Results:
cellForItemAtIndexPath called in all situations after prefetch method is called or never called and preparing and loading data up to user in prefetching method.

Actual Results:
cellForItemAtIndexPath not called after prefetching of item 1

Version:
iOS 10

Notes:


Configuration:
Simulator

Attachments:
'PrefetchingSample.zip' was successfully uploaded.