@CheckReturnValue
    public HttpResponse getInstance(String instanceId) {
        return sendGetRequest(INSTANCES + requireNonNull(instanceId, "instanceId"));
    }
Retrieves the registry information whose instance ID is the specified {@code instanceId} from the Eureka.
eureka/src/main/java/com/linecorp/armeria/internal/common/eureka/EurekaWebClient.java