Beware of deadlocks with serial queues

SerialQueuesDeadlock.swift

let customSerialQueue = DispatchQueue(label: "com.yogevsitton.MyApp.myCustomSerialQueue")

customSerialQueue.sync {
    // Synchronous code
    customSerialQueue.sync {
        // This code will never be executed and the app is now in deadlock
    }
}