Serializer

default ByteBuffer serializeToByteBuffer(String topic, T data) {
    return wrapNullable(serialize(topic, data));
}

default ByteBuffer serializeToByteBuffer(String topic, Headers headers, T data) {
    return wrapNullable(serialize(topic, headers, data));
}

ByteBufferSerializer

/** 
* Note that this method will modify the position and limit of the input ByteBuffer. 
* 
* @param topic   topic associated with data 
* @param data    typed data 
* @return serialized ByteBuffer
*/
@Override
public ByteBuffer serializeToByteBuffer(String topic, ByteBuffer data) {
    if (data == null) {
        return null;
    }

    // Consider that ByteBuffer#wrap(byte[]) return a ByteBuffer that does not need to call flip().
    if (data.position() > 0) {
        data.flip();
    }
    return data;
}

@Override
public ByteBuffer serializeToByteBuffer(String topic, Headers headers, ByteBuffer data) {
    return serializeToByteBuffer(topic, data);
}

Partitioner

default int partition(String topic, Object key, ByteBuffer keyBytes, Object value, ByteBuffer valueBytes, Cluster cluster) {
    return partition(topic, key, toNullableArray(keyBytes), value, toNullableArray(valueBytes), cluster);
}