docs: public void serialize(Map<String, T> map, JsonGenerator jsonGenerator) throws IOException {
          jsonGenerator.writeStartObject();
          for (Map.Entry<String, T> entry : map.entrySet()) {
              jsonGenerator.writeFieldName(entry.getKey());
              if (entry.getValue() == null) {
                  jsonGenerator.writeNull();
              } else {
                  serialize(entry.getValue(), jsonGenerator, true);
              }
          }
          jsonGenerator.writeEndObject();
      }