@Override public void serveSubscribeRequest( ByteString topic, SubscribeRequest subRequest, MessageSeqId consumeSeqId, Callback<SubscriptionData> callback, Object ctx) { if (fail) { callback.operationFailed(ctx, new PubSubException.ServiceDownException("Asked to fail")); return; } super.serveSubscribeRequest(topic, subRequest, consumeSeqId, callback, ctx); }