code: func (plugin *ExamplePlugin) producer() {
  	// Wait for the both event handlers to initialize.
  	time.Sleep(2 * time.Second)
  
  	// Synchronous message with protobuf-encoded data.
  	enc := &etcdexample.EtcdExample{
  		StringVal: "sync-dummy-message",
  		Uint32Val: uint32(0),
  		BoolVal:   true,
  	}
  	// Send several sync messages with offsets 0,1,...
  	plugin.Log.Infof("Sending %v Kafka notifications (protobuf) ...", syncMessageCount)
  	for i := 0; i < syncMessageCount; i++ {
  		err := plugin.kafkaSyncPublisher.Put("proto-key", enc)
  		if err != nil {
  			plugin.Log.Errorf("Failed to sync-send a proto message, error %v", err)
  		}
  	}
  
  	plugin.messagesSent = true
  }
docs: /*************
   * Producers *
   *************/
  // producer sends messages to a desired topic and in the manual mode also
  // to a specified partition.