title: Detecting USB power state
body: <p>Windows has the option of powering down certain peripherals, such as USB ports, to save power (this behavior can be enabled/disabled via Device Manager).  The power down happens under various conditions such as when the lid of a laptop is closed.  This is causing a problem for me as I have a GUI which talks to hardware attached to the USB port and communications are severed every time the laptop lid is closed.  Is there a way to programmatically detect this power-down (standby?) event before it happens and more gracefully shut down my USB device?  Is there a way to programmatically configure each of the system’s USB ports to disable this behavior?</p>
  
  <p>Right now I'm looking at <code>SystemEvents.PowerModeChanged</code>, is this the right event to detect this?</p>