code: func NewEventKey(k Key, ch rune, mod ModMask) *EventKey {
  	if k == KeyRune && (ch < ' ' || ch == 0x7f) {
  		// Turn specials into proper key codes.  This is for
  		// control characters and the DEL.
  		k = Key(ch)
  		if mod == ModNone && ch < ' ' {
  			switch Key(ch) {
  			case KeyBackspace, KeyTab, KeyEsc, KeyEnter:
  				// these keys are directly typeable without CTRL
  			default:
  				// most likely entered with a CTRL keypress
  				mod = ModCtrl
  			}
  		}
  	}
  	return &EventKey{t: time.Now(), key: k, ch: ch, mod: mod}
  }
docs: // NewEventKey attempts to create a suitable event.  It parses the various
  // ASCII control sequences if KeyRune is passed for Key, but if the caller
  // has more precise information it should set that specifically.  Callers
  // that aren't sure about modifier state (most) should just pass ModNone.