public InstanceInfo applicationInstance(ApplicationId applicationId) {
        return toInstanceInfo(send(request(HttpRequest.newBuilder(instancePath(applicationId))
                                                      .timeout(Duration.ofSeconds(20)),
                                           GET)),
                              applicationId);
    }
Returns instance info for the given application id.
hosted-api/src/main/java/ai/vespa/hosted/api/ControllerHttpClient.java