The relative priority at which you’d like a host to handle the task, specified as a floating point value between
0 (lowest priority) and
1 (highest priority).
- iOS 8.0+
- macOS 10.10+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
To provide hints to a host on how to prioritize URL session tasks from your app, specify a priority for each task. Specifying a priority provides only a hint and does not guarantee performance. If you don’t specify a priority, a URL session task has a priority of
default, with a value of
There are three named priorities you can employ, described in URL Session Task Priority.
You can specify or change a task’s priority at any time, but not all networking protocols respond to changes after a task has started. There is no API to let you determine the effective priority for a task from a host’s perspective.