title: How to minimise(Memory leak) the app memory in ARKit Scene Click on back button?
body: <p>How to minimize the app memory consumption in ARKit Scene after clicking on the back button?</p>
  
  <p>Because every time when I open an ARview in my App, the memory usage is increasing.
  When I go back then it does not free the memory and after opening an ARview again, the memory usages increases even further.</p>
  
  <pre class="lang-swift prettyprint-override"><code>class ARViewController: UIViewController, ARSCNViewDelegate {
  
      override func viewDidLoad() {
          super.viewDidLoad()
          setupScene()
          setupFocusSquare()
      }
  
      func setupScene() {
          sceneView.delegate = self
          sceneView.session = session
          sceneView.antialiasingMode = .multisampling4X
          sceneView.automaticallyUpdatesLighting = false
          sceneView.preferredFramesPerSecond = 60
          sceneView.contentScaleFactor = 1.3
          enableEnvironmentMapWithIntensity(25.0)
          if let camera = sceneView.pointOfView?.camera {
              camera.wantsHDR = true
              camera.wantsExposureAdaptation = true
              camera.exposureOffset = -1
              camera.minimumExposure = -1
              camera.maximumExposure = 3
          }
      }
  
      func setupFocusSquare() {
          focusSquare?.isHidden = true
          focusSquare?.removeFromParentNode()
          focusSquare = FocusSquare()
          sceneView.scene.rootNode.addChildNode(focusSquare!)
          textManager.scheduleMessage("TRY MOVING LEFT OR RIGHT", inSeconds: 5.0, messageType: .focusSquare)
      }
  }
  </code></pre>