dispatch_barrier_async equivalent in Swift 3

Question

Refactoring a colleague\'s code, and I\'m looking for the equivalent of dispatch_barrier_async in swift 3. There are a lot of queues at play, and his design is to b

Answer 1

The async() method has a flags parameter which accepts a .barrier option:

func subscribe(subscriber: DaoDelegate) {
  (self.subscribers.q).async(flags: .barrier) { 
    //...
  }
}