Prefix message annotation with x-opt- in observation support

Author: acogoluegnes

src/main/java/com/rabbitmq/client/amqp/observation/micrometer/DeliverContext.java

@@ -33,7 +33,7 @@ public class DeliverContext extends ReceiverContext<Message> {
   DeliverContext(String exchange, String routingKey, String queue, Message message) {
     super(
         (carrier, key) -> {
-          Object result = carrier.annotation(key);
+          Object result = carrier.annotation(Utils.annotationKey(key));
           if (result == null) {
             result = carrier.property(key);
           }

src/main/java/com/rabbitmq/client/amqp/observation/micrometer/PublishContext.java

@@ -37,7 +37,7 @@ public class PublishContext extends SenderContext<Message> {
       String routingKey,
       Message message,
       ObservationCollector.ConnectionInfo connectionInfo) {
-    super((carrier, key, value) -> carrier.annotation(key, value));
+    super((carrier, key, value) -> carrier.annotation(Utils.annotationKey(key), value));
     if (exchange == null && routingKey == null) {
       String to = message.to();
       String[] exRk = Utils.exchangeRoutingKeyFromTo(to);

src/main/java/com/rabbitmq/client/amqp/observation/micrometer/Utils.java

@@ -56,6 +56,10 @@ static String[] exchangeRoutingKeyFromTo(String to) {
     return exRk;
   }
 
+  static String annotationKey(String key) {
+    return "x-opt-" + key;
+  }
+
   // from Apache HttpComponents PercentCodec
   private static final int RADIX = 16;