title: preserveDrawingBuffer false - is it worth the effort?
body: <p>When using preserveDrawingBuffer for our context we need to take care of clearing the drawing buffer by our self. I use this technique in my app.</p>
  
  <p>I read some article that says - setting this flag to false can get better performances.</p>
  
  <p>In my app when setting to false, in some cases i need to take care of clearing the front buffer by myself because when no drawing is happening we can still see what was drawn before.</p>
  
  <p>My question, is it worth now to turn my app upside down and covering all the cases in order to get better performances? Is it really so much improving ?</p>
  
  <p>Is there any demo that shows the different in performances when this flag is true (and performing <code>gl.clear(..)</code>) compares to false ?</p>