protected function _subscribeMailbox(Horde_Imap_Client_Mailbox $mailbox, $subscribe)
{
// SUBSCRIBE/UNSUBSCRIBE returns no untagged information (RFC 3501
// [6.3.6 & 6.3.7])
$this->_sendCmd($this->_command($subscribe ? 'SUBSCRIBE' : 'UNSUBSCRIBE')->add($this->_getMboxFormatOb($mailbox)));
}