title: Transparent UINavigationBar, but with blur
body: <p>By default, the <code>UINavigationBar</code> (and this appears to be valid to <code>UITabBar</code> as well) has a blur effect and is tinted white (with some translucency).</p>
  
  <p>What I would like to have is a fully transparent (not translucent!) bar, and keep the blurriness of what's behind it. Here's a mockup:
  <img src="https://cl.ly/image/1Q3n1l3q3V0I/transparent%20bar.png" alt=""></p>
  
  <p>If I try to set a custom bar tint color like this:<br>
  <code>[[UINavigationBar appearance] setBarTintColor:someColorWithAlphaLessThanOne];</code><br>
  The bar will, however, be tinted with a color exactly the same RGB values, but alpha forced to 1. In other words, the bar will be opaque.</p>
  
  <p>If I set the navigation bar's background image to a new <code>UIImage</code>, then it will be fully transparent, but will not have the blur effect.</p>
  
  <p>How can I remove the white tint and keep the blur?</p>