Can you name the main tools and means used when working with GCD?

The main tools and means when working with GCD (Grand Central Dispatch) in iOS include:

• Dispatch Queues — the primary structures for managing tasks: serial and concurrent.
• Dispatch Groups — allow grouping multiple tasks and tracking their completion.
• Dispatch Semaphores — for managing access to resources and synchronization.
• Dispatch Work Items — objects that encapsulate tasks, which can be started, canceled, or waited upon.
• Dispatch Sources — for handling events such as timers or system signals.

Example of using GCD for asynchronous task execution:

dispatchQueue.async {
    // Perform heavy task in background
    let result = heavyComputation()
    DispatchQueue.main.async {
        // Update UI on main thread
        self.updateUI(with: result)
    }
}