title: How to emit items, one by one, from Collection with a delay in RxSwift
body: <p>I would like to create an Observable from anyCollection that will emit each element one by one, after a delay. Also, onNext I would like to perform some updates to the item (model).</p>
  
  <p>For example:</p>
  
  <p>// Feed all dogs, one by one, with an interval of 5 seconds.</p>
  
  <pre><code>class Dog {
      var name: String?
      var age: Int?
      var feeded = false
  
      init(_ name: String, _ age: Int){
          self.name = name
          self.age = age
      }
  }
  
  func feedDogs(){
      let dog1 = Dog("Ren", 3)
      let dog2 = Dog("Bega", 7)
      let dog3 = Dog("Xuxu", 11)
      let delay = 6 // seconds
  
      let allDogs = [dog1, dog2, dog3]
  
      // Observable....
  
      // Expected results after subscribe
      //   Start - &gt; 0 seconds
      // dog1.feeded // true
      //   time lapse -&gt; 6 seconds
      // dog2. feeded  // true
      //    timelapse -&gt; 12 seconds
      // dog3.feeded // true
  }
  </code></pre>
  
  <p>I tried to use "zip" like "zipWith" (in RxJava), but it seems that in RxSwift is not supported.</p>