title: RxSwift error using Sort on Variable<[Element]>
body: <p>I have a array like this:</p>
  
  <pre><code>    var arrayPoints:Variable&lt;[Point]&gt;?
  </code></pre>
  
  <p>Later the user can sort the listlike this:</p>
  
  <pre><code>  func orderPointsByDistance(){
         self.arrayPoints?.value.sort{ $0.stringDistance.compare($1.stringDistance) == .orderedAscending  }
    }
  </code></pre>
  
  <p>However i am receiving this error:</p>
  
  <pre><code>fatal error: Executing on backgound thread.
  Please use MainScheduler.instance.schedule to schedule work on main thread.: file /Users/dasilvans/Desktop/GeoPlay/Pods/RxSwift/RxSwift/Rx.swift, line 23
  </code></pre>
  
  <p>In a way I perceive the error, but do not know how to solve it.
  Any suggestion?</p>