private boolean isSimpleRequest(String... headers) {
        String contentType = requestHeaders.get(CONTENT_TYPE);
        String reqType = request.getType();

        if (HttpHelper.isSimpleMethod(reqType)) {
            if (reqType.equals(HttpHelper.POST)) {
                return HttpHelper.isSimpleContentType(contentType)
                        && (headers == null || HttpHelper.isSimpleHeader(headers));
            } else {
                return headers == null || HttpHelper.isSimpleHeader(headers);
            }
        }

        return false;
    }
@return if the request is simple, as defined by CORS spec
plugins/cors-policy/src/main/java/io/apiman/plugins/cors_policy/CorsConnector.java