feat: support both palyoads when polling

Author: gastonfournier

src/main/java/io/getunleash/repository/PollingFeatureFetcher.java

@@ -85,10 +85,13 @@ private Runnable runInitialFetch(final Consumer<UnleashException> handler) {
         return () -> {
             try {
                 ClientFeaturesResponse response = featureFetcher.fetchFeatures();
-                eventEmitter.update(response);
                 if (response.getStatus() == ClientFeaturesResponse.Status.CHANGED) {
-                    updateFeatures(response);
-                } else if (response.getStatus() == ClientFeaturesResponse.Status.UNAVAILABLE) {
+                    String currentState = applyClientFeatures(response);
+                    eventEmitter.update(ClientFeaturesResponse.updated(currentState));
+                } else {
+                    eventEmitter.update(response);
+                }
+                if (response.getStatus() == ClientFeaturesResponse.Status.UNAVAILABLE) {
                     if (unleashConfig.isSynchronousFetchOnInitialisation()) {
                         throw new UnleashException(
                                 String.format(
@@ -111,12 +114,15 @@ private Runnable runSteadyStateFetch(final Consumer<UnleashException> handler) {
             if (throttler.performAction()) {
                 try {
                     ClientFeaturesResponse response = featureFetcher.fetchFeatures();
-                    eventEmitter.update(response);
                     if (response.getStatus() == ClientFeaturesResponse.Status.CHANGED) {
-                        updateFeatures(response);
+                        String currentState = applyClientFeatures(response);
+                        eventEmitter.update(ClientFeaturesResponse.updated(currentState));
                     } else if (response.getStatus() == ClientFeaturesResponse.Status.UNAVAILABLE) {
+                        eventEmitter.update(response);
                         throttler.handleHttpErrorCodes(response.getHttpStatusCode());
                         return;
+                    } else {
+                        eventEmitter.update(response);
                     }
                     throttler.decrementFailureCountAndResetSkips();
                 } catch (UnleashException e) {
@@ -130,12 +136,14 @@ private Runnable runSteadyStateFetch(final Consumer<UnleashException> handler) {
         };
     }
 
-    private void updateFeatures(ClientFeaturesResponse response)
+    private String applyClientFeatures(ClientFeaturesResponse response)
             throws YggdrasilInvalidInputException {
         String clientFeatures = response.getClientFeatures().get();
         this.engine.takeState(clientFeatures);
-        this.featureBackupHandler.write(clientFeatures);
+        String currentState = this.engine.getState();
+        this.featureBackupHandler.write(currentState);
         eventEmitter.ready();
+        return currentState;
     }
 
     public Integer getFailures() {

src/main/java/io/getunleash/repository/StreamingFeatureFetcherImpl.java

@@ -131,7 +131,7 @@ synchronized void handleStreamingUpdate(String data) throws YggdrasilInvalidInpu
         String currentState = engine.getState();
         featureBackupHandler.write(currentState);
 
-        ClientFeaturesResponse response = ClientFeaturesResponse.updated(data);
+        ClientFeaturesResponse response = ClientFeaturesResponse.updated(currentState);
         eventDispatcher.update(response);
 
         if (!ready) {