Kafka Sink Topic was overwritten by Kafka Source Topic

[lxw]

Hi,All:

   I use Kafka Source to read events from one Kafka topic and write events to 
another Topic with Kafka Sink, 
the Kafka Sink topic configuration is not work, flume still write events to 
Kafka source Topic (sourceTopic).

  agent_myAgent.sources.kafkaSource.topic = sourceTopic
  agent_myAgent.sinks.kafkaSink.topic = sinkTopic
 
  SourceCode in "org.apache.flume.source.kafka.KafkaSource.process()" :
   // Add headers to event (topic, timestamp, and key)
          headers = new HashMap<String, String>();
          headers.put(KafkaSourceConstants.TIMESTAMP,
                  String.valueOf(System.currentTimeMillis()));
          headers.put(KafkaSourceConstants.TOPIC, topic);
 
 and in Kafka Sink properties:
 
The topic in Kafka to which the messages will be published. If this parameter 
is configured, messages will be published to this topic. If the event header 
contains a ??topic?? field, the event will be published to that topic 
overriding the topic configured here.

  SourceCode in "org.apache.flume.sink.kafka.KafkaSink.process()":
  if ((eventTopic = headers.get(TOPIC_HDR)) == null) {
            eventTopic = topic;
   }

  In my case, how I can fix this problem?
  Flume version is 1.6.0.
  Thanks!