Creates a download task that retrieves the contents of a URL based on the specified URL request object and saves the results to a file.
- iOS 7.0+
- macOS 10.9+
- tvOS 9.0+
- watchOS 2.0+
A URL request object that provides the URL, cache policy, request type, body data or body stream, and so on.
The new session download task.
By creating a task based on a request object, you can tune various aspects of the task’s behavior, including the cache policy and timeout interval.
After you create the task, you must start it by calling its
resume() method. The task calls methods on the session’s delegate to provide you with progress notifications, the location of the resulting temporary file, and so on.