Make property volatile

Author: acogoluegnes

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

@@ -64,7 +64,7 @@ class StreamConsumer implements Consumer {
   private final boolean sac;
   private final OffsetSpecification initialOffsetSpecification;
   private final Lock lock = new ReentrantLock();
-  private boolean consuming = false;
+  private volatile boolean consuming = false;
 
   @SuppressFBWarnings("CT_CONSTRUCTOR_THROW")
   StreamConsumer(