MessageConsumer unregister() should return a Future<Void>

src/main/java/io/vertx/core/eventbus/MessageConsumer.java

@@ -13,6 +13,7 @@ package io.vertx.core.eventbus;
 
 import io.vertx.codegen.annotations.VertxGen;
 import io.vertx.core.AsyncResult;
+import io.vertx.core.Future;
 import io.vertx.core.Handler;
 import io.vertx.core.streams.ReadStream;
 
@@ -92,7 +93,7 @@ public interface MessageConsumer<T> extends ReadStream<Message<T>> {
   /**
    * Unregisters the handler which created this registration
    */
-  void unregister();
+  Future<Void> unregister();
 
   /**
    * Unregisters the handler which created this registration

src/main/java/io/vertx/core/eventbus/impl/HandlerRegistration.java

@@ -121,8 +121,10 @@ public class HandlerRegistration<T> implements MessageConsumer<T>, Handler<Messa
   }
 
   @Override
-  public void unregister() {
-    doUnregister(null);
+  public Future<Void> unregister() {
+    Promise<Void> promise = Promise.promise();
+    doUnregister(promise);
+    return promise.future();
   }
 
   @Override