PHPMailer\PHPMailer\SMTP::close PHP Method

    public function close()
    {
        $this->setError('');
        $this->server_caps = null;
        $this->helo_rply = null;
        if (is_resource($this->smtp_conn)) {
            // close the connection and cleanup
            fclose($this->smtp_conn);
            $this->smtp_conn = null;
            //Makes for cleaner serialization
            $this->edebug('Connection: closed', self::DEBUG_CONNECTION);
        }
    }