Comment éviter la perte de données avec la redirection PHP ?

$data = [
	'username' => 'guanhuicoder',
	'redirect_url' => './index.php'
	'email' => 'guanhuicoder@code.com'
];

$data = [
	'username' => 'guanhuicoder',
	'redirect_url' => './index.php'
	'email' => 'guanhuicoder@code.com'
];

$data = json_encode($data);

session_start();

$_SESSION['data'] = $data;

session_start();

$data = $_SESSION['data'];

unset($_SESSION['data']);

$data = json_decode($data);