static boolean isSuccess(int statusCode) {
        return statusCode / 100 == 2 || statusCode == 404 || statusCode == 412;
    }
Retries all IOExceptions, unless error rate has converged to a value higher than the threshold,
or the user has turned off retries for this type of operation.
vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/HttpRequestStrategy.java