clear method
Deletes all securely stored data.
Implementation
Future<void> clear() async {
if (_credentialsFile.existsSync()) {
await _credentialsFile.delete();
}
final tempFile = File('${_credentialsFile.path}.tmp');
if (tempFile.existsSync()) {
await tempFile.delete();
}
if (_keyFile.existsSync()) {
await _keyFile.delete();
}
}