Is it possible to implement your own queue structure?

Yes, it is possible to implement a custom queue structure in iOS. For example, you can create a class that stores elements in an array and provides methods for adding (enqueue) and removing (dequeue) elements based on the FIFO (first-in, first-out) principle. This can be useful if standard classes like DispatchQueue are not suitable for specific tasks.

Here's a simple queue example in Swift:

class Queue<T> {
    private var elements: [T] = []

    func enqueue(_ element: T) {
        elements.append(element)
    }

    func dequeue() -> T? {
        guard !elements.isEmpty else { return nil }
        return elements.removeFirst()
    }

    var isEmpty: Bool {
        return elements.isEmpty
    }
}

let queue = Queue<Int>()
queue.enqueue(1)
queue.enqueue(2)
print(queue.dequeue()) // 1
print(queue.dequeue()) // 2