How does it work?
InputCtrl.SimKeyPressBool() is an alternative to Unity's Input.GetKey().
GUIButton gets the correct KeyCode by parsing its text component. Then on the button press this KeyCode is added to the declared HashSet ForcedKeys. The InputCtrl.SimKeyPressBool checks if ForcedKeys contains the KeyCode and returns bool accordingly.
It provides O(1) search, insertion and deletion.