title: RxSwift double mapping in tableView.rx.itemSelected
body: <p>I want to get object from <code>tableView.rx.itemSelected</code> and after process it. This method return <code>IndexPath</code>, so I can map this value. But how to get object at index from the <code>ViewModel</code>?</p>
  
  <pre><code>struct ViewModel {
      var items: Observable&lt;[Item]&gt;
  }
  </code></pre>
  
  <p>Approximate I expect something like this (but this flow is wrong):</p>
  
  <pre><code>tableView.rx.itemSelected
          .map { indexPath -&gt; Item in 
          return viewModel.items.map {$0[indexPath.row]}
          }
          ..subscribe(onNext: { [unowned self] item in
          //other actions with Item object
          })
          .disposed(by: disposeBag)
  </code></pre>
  
  <p>I showed somewhere this possibility, but cant recollect it. Have you some idea how to do it?</p>