code: protected void bodyToJsonUtf8(JsonGenerator generator)
        throws IOException {
  
      generator.writeObjectField("dataset", datasetLevel);
      generator.writeObjectFieldStart("file");
      for (Map.Entry<String, Map<String, Object>> entry : fileLevel.entrySet()) {
        generator.writeObjectField(entry.getKey(), entry.getValue());
      }
      generator.writeEndObject();
  
    }
docs: Write this object out to an existing JSON stream