private long qAgeNS(HttpRequest request) {
        Operation oldest = operations.peek();
        return (oldest != null)
                ? (request.relativeCreatedAtNanoTime() - oldest.request.relativeCreatedAtNanoTime())
                : 0;
    }
Attempts to dispatch the first enqueued visit operations, and returns whether this was successful.
vespaclient-container-plugin/src/main/java/com/yahoo/document/restapi/resource/DocumentV1ApiHandler.java