Vertx ConsumeEvent - document failure handling

docs/src/main/asciidoc/reactive-event-bus.adoc

@@ -211,6 +211,13 @@ public void consume(Message<String> msg) {
 }
 ----
 
+=== Handling Failures
+
+If a method annotated with `@ConsumeEvent` throws an exception then:
+
+* if a reply handler is set then the failure is propagated back to the sender via an `io.vertx.core.eventbus.ReplyException` with code `ConsumeEvent#FAILURE_CODE` and the exception message,
+* if no reply handler is set then the exception is rethrown (and wrapped in a `RuntimeException` if necessary) and can be handled by the default exception handler, i.e. `io.vertx.core.Vertx#exceptionHandler()`.
+
 == Sending messages
 
 Ok, we have seen how to receive messages, let's now switch to the _other side_: the sender.

extensions/vertx/runtime/src/main/java/io/quarkus/vertx/ConsumeEvent.java

@@ -40,11 +40,19 @@
  * </pre>
  * 
  * <p>
- * The CDI request context is active during notification of the registered message consumer.
+ * The CDI request context is always active during notification of the registered message consumer.
+ * <p>
+ * If a method annotated with {@link ConsumeEvent} throws an exception then:
+ * <ul>
+ * <li>if a reply handler is set the failure is propagated back to the sender via an
+ * {@link io.vertx.core.eventbus.ReplyException} with code {@link #FAILURE_CODE} and the exception message,</li>
+ * <li>if no reply handler is set then the exception is rethrown (and wrapped in a {@link java.lang.RuntimeException} if
+ * necessary) and can be handled by the default exception handler, i.e. {@link io.vertx.core.Vertx#exceptionHandler().}</li>
+ * </ul>
  * 
  * @see io.vertx.core.eventbus.EventBus
  */
-@Target({ METHOD })
+@Target(METHOD)
 @Retention(RUNTIME)
 public @interface ConsumeEvent {