@Override
    public String toString() {
        String bodyStr = (body == null || body.length == 0) ? "[empty]" : "[omitted]";
        return "Request to " + uri + ", headers: " + headers + ", body: " + bodyStr;
    }
@return a mutable attribute map for this request.
application/src/main/java/com/yahoo/application/container/handler/Request.java