import Combine
import Dispatch

func randomInt() -> Deferred<Future<Int, Never>> {
  Deferred {
    Future { promise in
      DispatchQueue.global().asyncAfter(deadline: .now() + 0.01) {
        promise(.success(.random(in: .min ... .max)))
      }
    }
  }
}

let q = PublisherQueue(size: .max)
var subscriptions = Set<AnyCancellable>()
var resultCount = 0
let group = DispatchGroup()

for _ in 1 ... 1000 {
  group.enter()
  q.queuedPublisher(randomInt()).sink(receiveCompletion: { _ in group.leave() }) { number in
    resultCount += 1
  }.store(in: &subscriptions)
}

group.wait()
print(resultCount, "results") // 1000 results