public function complete(Horde_Imap_Client_Interaction_Server_Tagged $resp)
    {
        if (isset($this->_commands[$resp->tag])) {
            $cmd = $this->_commands[$resp->tag];
            $cmd->response = $resp;
            unset($this->_todo[$resp->tag]);
        } else {
            /* This can be reached if a previous pipeline action was aborted,
             * e.g. via an Exception. */
            $cmd = null;
        }

        return $cmd;
    }