debugDescribeKeys method Null safety
override
    Returns a short and readable description of the key combination.
Intended to be used in debug mode for logging purposes. In release mode, debugDescribeKeys returns an empty string.
Implementation
@override
String debugDescribeKeys() {
  String result = '';
  assert(() {
    final List<String> keys = <String>[
      if (control) 'Control',
      if (alt) 'Alt',
      if (meta) 'Meta',
      if (shift) 'Shift',
      trigger.debugName ?? trigger.toStringShort(),
    ];
    result = keys.join(' + ');
    return true;
  }());
  return result;
}