function __construct($starting_url, $yadis_url, $services, $session_key)
{
// The URL that was used to initiate the Yadis protocol
$this->starting_url = $starting_url;
// The URL after following redirects (the identifier)
$this->yadis_url = $yadis_url;
// List of service elements
$this->services = $services;
$this->session_key = $session_key;
// Reference to the current service object
$this->_current = null;
// Stale flag for cleanup if PHP lib has trouble.
$this->stale = false;
}