almaleh

let serial1 = DispatchQueue(label: "com.besher.serial1")
let serial2 = DispatchQueue(label: "com.besher.serial2")

serial1.async {
    for _ in 0..<5 { print("🔵") }
}

serial2.async {
    for _ in 0..<5 { print("🔴") }
}

almaleh

let imageProcessingQueue = DispatchQueue(label: "com.besher.image-processing")

func processImageAsync(data: Data, completion: @escaping (UIImage?) -> Void) {
    guard let image = UIImage(data: data) else {
        completion(nil)
        return
    }

    imageProcessingQueue.async {
        let processedImage =  self.upscaleAndFilter(image: image)

almaleh

let imageProcessingQueue = DispatchQueue(label: "com.besher.image-processing")

func processImageAsync(data: Data) -> UIImage? {
    guard let image = UIImage(data: data) else { return nil }
    
    imageProcessingQueue.async {
        let processedImage = upscaleAndFilter(image: image)
        return processedImage
    }
}

almaleh

DispatchQueue.global().async {
    print("Inside")
}
print("Outside")
// Potential console output (based on QoS): 
// Outside
// Inside

almaleh

DispatchQueue.global().sync {
    print("Inside")
}
print("Outside")
// Console output:
// Inside
// Outside

almaleh

DispatchQueue.global().async {
    for i in 0..<10 {
        print(i)
    }

    for _ in 0..<10 {
        print("🔵")
    }

    for _ in 0..<10 {

almaleh

let item = DispatchWorkItem(qos: .utility) {
    print("Work item to be executed later")
}

almaleh

DispatchQueue.global().async {
    print("Anonymous closure")
}

almaleh

let concurrent = DispatchQueue(label: "com.besher.serial-queue", attributes: .concurrent)
concurrent.sync {
    print("Private concurrent queue")
}

almaleh

let serial = DispatchQueue(label: "com.besher.serial-queue")
serial.async {
    print("Private serial queue")
}