public void init() {
        GetAllInstancesRequest getAllInstancesRequest = new GetAllInstancesRequest();
        getAllInstancesRequest.setNamespace(nameSpace);
        getAllInstancesRequest.setService(serviceName);
        this.currentData = consumerAPI.getAllInstance(getAllInstancesRequest);
        this.watchExecutor = Executors.newSingleThreadScheduledExecutor();
        this.watchExecutor.scheduleWithFixedDelay(this::watchService, properties.getLookupInterval(), properties.getLookupInterval(), TimeUnit.MILLISECONDS);
    }
observe the providers from polaris and notify the consumers

@author <a href=mailto:bner666@gmail.com>ZhangLibin</a>
registry/registry-polaris/src/main/java/com/alipay/sofa/rpc/registry/polaris/PolarisWatcher.java