title: Update the visualization of a set of geometries on Open3D in Non-Blocking mode
body: <p>I'm trying to update a set of geometries on <code>open3d==0.12.0</code> using <code>vis.update_geometry(geometry)</code> that updates a single geometry. However, the current solution is a bit slow compared to <code>open3d==0.7.0</code> using <code>vis.update_geometry()</code> that updates all the geometries.
  Is there any other solution? Here is my current solution:</p>
  <pre><code>import open3d as o3d
  
  if __name__ == '__main__':
      # Create Open3d visualization window
      vis = o3d.visualization.Visualizer()
      vis.create_window()
      vis.create_window(&quot;BASSAR&quot;)
      vis.get_render_option().background_color = [0.75, 0.75, 0.75]
      vis.get_render_option().mesh_show_back_face = True
  
      # adding geometries : 
      for g in geometries:
          vis.add_geometry(g)
  
      while True:
          # updating geometries:
          # ...
          
          for g in geometries:
              vis.update_geometry(g)
  
          vis.poll_events()
          vis.update_renderer()
  
  </code></pre>