public function markAuthenticationCall($auth)
{
// store where the authentication has been checked and the result
$dbg = debug_backtrace();
$this->_authentication_caller = array('file' => $dbg[1]['file'], 'line' => $dbg[1]['line'], 'method' => $dbg[1]['class'] . '::' . $dbg[1]['function'], 'result' => (bool) $auth);
}