class ResponseImpl extends Response {

    @Override
    public String getHeaderString(String name) {
        List<Object> headers = getMetadata().get(name);
        if (headers == null) {
            return null;
        }
        List<String> headerStrings = headers.stream().map(HeaderHelper::getHeaderAsString).collect(toList());
        return HeaderHelper.convertToString(headerStrings);
    }

    protected  ResponseImpl(int status, Object entity, Annotation[] entityAnnotations, MultivaluedMap<String, Object> headers);

}