Connection never close for REST client

[Callimard]

Hello,

When you use the KucoinRestClient, it make your process never end because it is impossible to close the object.
I test this code:

public static void main(String[] args) throws IOException {
        KucoinRestClient restClient = new KucoinClientBuilder()
                .withBaseUrl("https://api.kucoin.com")
                .withApiKey("xxxxxxxxxxxxxxxxxxxxx", "yyyyyyyyyyyyyyyyyyyyyy", "zzzzzzzzzzzzzzzzzzzzzzzz")
                .buildRestClient();

        System.out.println("current price " + restClient.symbolAPI().getTicker("BTC-USDT").getPrice());
    }

And I get the result but my process never end.

Is it normal? Is there a way to close the KucoinRestClient?