public static ObjectMapper defaultObjectMapper() {
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
        mapper.addMixIn(ChatFunction.class, ChatFunctionMixIn.class);
        mapper.addMixIn(ChatCompletionRequest.class, ChatCompletionRequestMixIn.class);
        mapper.addMixIn(ChatFunctionCall.class, ChatFunctionCallMixIn.class);
        return mapper;
    }
Shuts down the OkHttp ExecutorService.
The default behaviour of OkHttp's ExecutorService (ConnectionPool)
is to shut down after an idle timeout of 60s.
Call this method to shut down the ExecutorService immediately.
service/src/main/java/com/theokanning/openai/service/OpenAiService.java