What level of service quality is considered the highest or most priority in DispatchQos?

In iOS, when working with GCD (Grand Central Dispatch), the Quality of Service (QoS) level determines the priority of task execution. The highest priority is userInteractive. It is intended for tasks that affect the interface and must be executed as quickly as possible to ensure app responsiveness (e.g., animations, user input processing).

The main QoS levels in descending order of priority:

• userInteractive — the highest priority, for tasks requiring immediate response.
• userInitiated — tasks initiated by the user that should complete quickly.
• default — the default level.
• utility — for long-running tasks with low priority.
• background — for background tasks that do not affect user experience.

Example of creating a queue with high priority:

let queue = DispatchQueue.global(qos: .userInteractive)
queue.async {
    // high priority code
}