WriteKafkaP is a processor which acts as a Kafka sink. It receives
items of type Map.Entry and sends a ProducerRecord to the
specified topic with key/value parts which will be serialized according
to the Kafka producer configuration. The key and value serializers set
in the properties should be able to handle the keys and values received
by the processor.
Internally, a single KafkaProducer is created per node, which is
shared among all Processor instances on that node.
See the Kafka code sample for a fully worked example.