restore method
Restores the saved state. Call it before runApp so the window does not
jump once the stored position is available.
Implementation
Future<void> restore() async {
try {
if (!await _storage.load()) return;
} catch (_) {
// No usable local storage: keep the defaults.
return;
}
_isVisible = _storage.readBool(_visibleKey) ?? _isVisible;
_isExpanded = _storage.readBool(_expandedKey) ?? _isExpanded;
final x = _storage.readDouble(_offsetXKey);
final y = _storage.readDouble(_offsetYKey);
if (x != null && y != null) _offset = Offset(x, y);
_notify();
}