title: Rxjava - Iterate the list with batch
body: <p>i have a list of some strings, where i need to iterate the list in batch.<br>
  Example :</p>
  
  <pre><code>val list = ["a","b","c","d","e","f"]
  Observable.fromIteratable(list)
            .map{
            //here i need to get 4 items at a time
            //like in first iteration i need to get ["a","b","c","d"]
            //in second iteration i need to get ["e","f"]
          }
  </code></pre>
  
  <p>Is there is any option to do perform this ?</p>