Playing with RxSwift Scheduler

RxSandbox.swift

import UIKit
import RxSandbox
import RxSwift
import PlaygroundSupport

func which() -> String {
  return Thread.isMainThread ? "main" : "background"
}

let disposeBag = DisposeBag()

let observable = Observable<String>.create { observer -> Disposable in
  Thread.sleep(forTimeInterval: 5)
  observer.onNext("YO!😎 from \(which()).")
  observer.onCompleted()
  return Disposables.create()
}

observable
  .subscribeOn(ConcurrentDispatchQueueScheduler(qos: .default))
  .observeOn(MainScheduler.instance)
  .subscribe(onNext: { (message: String) in
    print("\(message) (Here is \(which()))")
  })
  .disposed(by: disposeBag)

PlaygroundPage.current.liveView = UIView()