Open Radar

 
Description of the problem:

Fetching assets (PHAsset) takes way too much time (more than 3 seconds) when performed on a device with more than 50 000  assets. This latency even occures when setting a fetchLimit of 1 (or any other small number).

How to reproduce:
- Pick a phone that has at least 50 000 assets.
- Get a reference to the “Recent” album: `let collection = PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .smartAlbumUserLibrary, options: nil).firstObject`
- Create a fetch options object and fetch the assets:
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.image.rawValue)
let fetchResult = PHAsset.fetchAssets(in: collection, options: fetchOptions)

Expected result:
The assets should be fetched in a reasonable amount of time.

Observed result:
It takes more than 3 seconds to fetch the assets.