title: How to change size of thumb image of UISlider programmatically
body: <p>I would like to make the custom UISlider,
  something like this  </p>
  
  <p>|o----------| -> |-----O------|   -> |------------〇|</p>
  
  <p>the <code>thumbImage</code> will be small at the minimum value, it will increase the size during the slider value increase, otherwise it will decrease.</p>
  
  <p>is anyone know how to do it?</p>