Github user GJL commented on a diff in the pull request:
https://github.com/apache/flink/pull/5410#discussion_r190650550
--- Diff:
flink-connectors/flink-connector-rabbitmq/src/main/java/org/apache/flink/streaming/connectors/rabbitmq/RMQSinkPublishOptions.java
---
@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.streaming.connectors.rabbitmq;
+
+import com.rabbitmq.client.AMQP.BasicProperties;
+
+/**
+ * The message computation provides methods to compute the message routing
key and/or the properties.
+ *
+ * @param <IN> The type of the data used by the sink.
+ */
+public interface RMQSinkPublishOptions<IN> {
--- End diff --
This must extend `java.io.Serializable` because `RMQSink` has a
non-transient field of this type.
---
