Return copy of replicas

Author: acogoluegnes

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

@@ -2263,9 +2263,12 @@ public Broker getLeader() {
       return leader;
     }
 
-    @SuppressFBWarnings("EI_EXPOSE_REP2")
     public List<Broker> getReplicas() {
-      return replicas;
+      return this.replicas.isEmpty() ? Collections.emptyList() : new ArrayList<>(this.replicas);
+    }
+
+    boolean hasReplicas() {
+      return !this.replicas.isEmpty();
     }
 
     public String getStream() {

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

@@ -224,7 +224,7 @@ List<BrokerWrapper> findCandidateNodes(String stream, boolean forceLeader) {
     }
     candidates.add(new BrokerWrapper(leader, true));
 
-    if (!forceLeader && !streamMetadata.getReplicas().isEmpty()) {
+    if (!forceLeader && streamMetadata.hasReplicas()) {
       candidates.addAll(
           streamMetadata.getReplicas().stream()
               .map(b -> new BrokerWrapper(b, false))