private void watchService() {
        try {
            GetAllInstancesRequest getAllInstancesRequest = new GetAllInstancesRequest();
            getAllInstancesRequest.setNamespace(nameSpace);
            getAllInstancesRequest.setService(serviceName);
            Map<String, String> parameters = new HashMap<>();
            parameters.put("protocol", protocol);
            getAllInstancesRequest.setMetadata(parameters);
            InstancesResponse response = consumerAPI.getAllInstance(getAllInstancesRequest);
            this.currentData = response;
            ProviderGroup providerGroup = new ProviderGroup(currentProviders());
            listeners.stream().filter(Objects::nonNull).forEach(l -> l.updateProviders(providerGroup));
        } catch (Exception e) {
            LOGGER.error(LogCodes.getLog(LogCodes.ERROR_WATCH_HEALTH, "Polaris"), e);
        }
    }
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