fix BufferedAsyncConsumer

Author: lecousin

net.lecousin.core/src/main/java/net/lecousin/framework/concurrent/util/BufferedAsyncConsumer.java

@@ -87,7 +87,7 @@ public IAsync<TError> end() {
 		synchronized (queue) {
 			if (error != null)
 				return new Async<>(error);
-			if (queue.isEmpty())
+			if (lastOperation == null && queue.isEmpty())
 				return consumer.end();
 			end = new Async<>();
 			return end;