What methods can be used to perform background tasks in an application?

In iOS, there are several approaches to perform tasks in the background:

• Background Tasks (BGTaskScheduler) — a modern API for scheduling background tasks that the system executes at optimal times.
• Background Fetch — allows the app to periodically update content in the background.
• NSURLSession with background configuration — for uploading and downloading data in the background.
• Dispatch Queues (GCD) — for executing asynchronous tasks, but they only work while the app is active.
• OperationQueue — similar to GCD but with more flexible dependency management.
• Silent Push Notifications — allow waking up the app to perform tasks in the background.

Example of using BGTaskScheduler:

import BackgroundTasks

func scheduleAppRefresh() {
    let request = BGAppRefreshTaskRequest(identifier: "com.example.apprefresh")
    request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60) // in 15 minutes
    do {
        try BGTaskScheduler.shared.submit(request)
    } catch {
        print("Failed to schedule task: \(error)")
    }
}

BGTaskScheduler.shared.register(forTaskWithIdentifier: "com.example.apprefresh", using: nil) { task in
    // Executing background task
    task.setTaskCompleted(success: true)
}