title: How to enable Android Things USB modifier GUI/Window Key -> onKeyDown()
body: <p>I've connected an USB keyboard to the Raspberry Pi 3 with Android Things.</p>
  
  <p>All is working fine except the modifier key: GUI/Window</p>
  
  <p>Is there a way to activate/enable this key that trigger the onKeyDown() Event?</p>
  
  <p>Because at this time if I pressed the "GUI/Window" modifier key on my PC Keyboard... no onKeyDown() is triggered.</p>