Creating client without subscribing to a topic causes infinite loop

[nevries]

Just try that:

public static void main(String[] args) throws InterruptedException {
    ExternalTaskClient client = ExternalTaskClient.create()
        .baseUrl("http://localhost:8080/engine-rest")
        .asyncResponseTimeout(1000)
        .build();

    Thread.sleep(300_000);
}

and observe CPU utilization. It's propably this loop: https://github.com/camunda/camunda-external-task-client-java/blob/11a7fcf44e11375d85759494e20f25641fcff3e0/client/src/main/java/org/camunda/bpm/client/topic/impl/TopicSubscriptionManager.java#L85-L92