How to go full screen/full resolution?

Unity Engine
,
1

How do I go fullscreen programmatically without getting any letterboxing?

2 
public void ToggleFullscreen(bool fullscreen)
     {
         Screen.fullScreen = fullscreen;
         if (Screen.fullScreen)
         {
             Screen.fullScreenMode = FullScreenMode.ExclusiveFullScreen;
         }
         else
         {
             Screen.fullScreenMode = FullScreenMode.Windowed;
         }
     }

something like this should work