public function providerReadWrite()
{
// This key is needed in order not to break your real data
$key = hash('sha256', json_encode([__CLASS__, __METHOD__, __FILE__, __LINE__]));
return [[$key . '_test1', 'data1'], [$key . '_test1', (object) ['key' => 'value']], [$key . '_test1', ['key' => 'value']], [$key . '_test1', null], [$key . '_test1', new stdClass()]];
}