contenu de $_SESSION pendant une requete de progression de l'upload
Array
(
    [symfony/user/sfUser/lastRequest] => 1359119874
    [symfony/user/sfUser/authenticated] => 1
    [symfony/user/sfUser/credentials] => Array
        (
            [0] => superadmin
        )

    [symfony/user/sfUser/attributes] => Array
        (
            [symfony/user/sfUser/attributes] => Array
                (
                )

            [sfGuardSecurityUser] => Array
                (
                    [user_id] => 1
                )

        )

    [symfony/user/sfUser/culture] => fr
    [debug_cnt] => 9
    [debug_progress] => 0
)