public String render(){
        StringBuilder res = new StringBuilder();
        if(statusCode != 0)
            res.append("HTTP/1.0 ").append(statusCode).append(" \n");
        if(header == null)
            res.append(body.render());
        else if(body == null)
            res.append(header.render());
        else{
            res.append(header.render());
            res.append("\n");
            res.append(body.render());
        }
        
        return res.toString();
    }