public function readMailbox()
    {
        $msg_cnt = imap_num_msg($this->conn);

        $messages = [];
        for ($i = 1; $i <= $msg_cnt; $i++) {
            $header = imap_headerinfo($this->conn, $i);
            $messages[] = [
                'index'     => trim($header->Msgno),
                'header'    => $header,
                'structure' => imap_fetchstructure($this->conn, $i)
            ];
        }
        $this->messages = $messages;
        return $this->messages;
    }