Document casting trick for Avro value serializer in KafkaIO

Consider we want to write Avro values to Kafka with for example the following code:

KafkaIO.Write<String, GenericRecord> stringsToKafka =
 KafkaIO.<String, GenericRecord>write()
  .withBootstrapServers(bootstrapServers)
  .withTopic(topic)
  .withKeySerializer(StringSerializer.class)
  .withValueSerializer(KafkaAvroSerializer.class)
  .withProducerConfigUpdates(producerConfigUpdates);

 The KafkaAvroSerializer.class argument can't be passed as would normally be the case in Producer option: value.serializer=io.confluent.kafka.serializers.KafkaAvroSerializer

So the question then is which class should we pass or how to cast. IntelliJ IDEA suggests a cast which doesn't compile.

In the end the answer is simply:

  .withValueSerializer((Class)KafkaAvroSerializer.class) 

I think it's worth documenting this little trick more clearly in the Javadoc of KafkaIO to prevent others from bumping into the same issue.