public MultiPartStreamer addBytes(String name, byte[] bytes) {
        return addData(name, "application/octet-stream", null, () -> new ByteArrayInputStream(bytes));
    }
Adds the given data as a named part in this, using the {@code "application/octet-stream" content type}.
hosted-api/src/main/java/ai/vespa/hosted/api/MultiPartStreamer.java