Something surprising I learned recently is that this is an anti-pattern when building an iOS app. iOS has a memory compressor, so if you try to purge resources in a low-memory situation, it can cause memory use to spike as the things you're trying to free get decompressed.

The SDK provides a notification when memory pressure is high, so people try to get aggressive and purge their caches and unused assets when that notification arrives, but that only makes the problem worse.