Simplify super stream routing settings

Author: acogoluegnes

src/main/java/com/rabbitmq/stream/impl/StreamProducerBuilder.java

@@ -136,17 +136,24 @@ public ProducerBuilder routing(
       Function<Message, String> routingKeyExtractor,
       RoutingType routingType,
       ToIntFunction<String> hash) {
-    if ((routingKeyExtractor == null && routingType == null)
-        || (routingKeyExtractor != null && routingType != null)) {
-      this.routingKeyExtractor = routingKeyExtractor;
-      this.routingType = routingType;
-    } else {
+    if (routingKeyExtractor == null || routingType == null) {
       throw new IllegalArgumentException(
-          "both routing key extractor and routing type must be " + "non-null");
+          "both routing key extractor and routing type must be non-null");
+    }
+    this.routingKeyExtractor = routingKeyExtractor;
+    this.routingType = routingType;
+    if (hash != null) {
+      this.hash = hash;
     }
     return this;
   }
 
+  void resetRouting() {
+    this.routingKeyExtractor = null;
+    this.routingType = null;
+    this.hash = null;
+  }
+
   public Producer build() {
     if (subEntrySize == 1 && compression != null) {
       throw new IllegalArgumentException(

src/main/java/com/rabbitmq/stream/impl/SuperStreamProducer.java

@@ -44,7 +44,7 @@ class SuperStreamProducer implements Producer {
     this.superStream = superStream;
     this.producerBuilder = producerBuilder.duplicate();
     this.producerBuilder.stream(null);
-    this.producerBuilder.routing(null, null);
+    this.producerBuilder.resetRouting();
   }
 
   @Override