Gets the cached URL response for a data task, passing it to the provided completion handler.
- iOS 8.0+
- macOS 10.10+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The data task whose cached URL response is desired.
A completion handler that receives the cached URL response for the data task's request, or
nilif no response is found in the cache.