public static <K, V> KVSerde<K, V> of(Serde<K> keySerde, Serde<V> valueSerde) {
    return new KVSerde<>(keySerde, valueSerde);
  }
A serializer that serves one of the following two purposes:
<ol>
  <li>When used for input/output streams, serves as an indication to the framework that messages are keyed and
  should be deserialized as K-V pairs.</li>
  <li>When used for a key or value of type KV, serializes the key and value pair using the provided serdes.</li>
</ol>

@param <K> type of the key in the message
@param <V> type of the value in the message
samza-api/src/main/java/org/apache/samza/serializers/KVSerde.java