in src/main/java/org/apache/sling/distribution/journal/kafka/KafkaClientProvider.java [228:235]
private Map<String, Object> producerConfig(Object serializer) {
Map<String, Object> config = commonConfig();
config.put(REQUEST_TIMEOUT_MS_CONFIG, requestTimeout);
config.put(KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
config.put(VALUE_SERIALIZER_CLASS_CONFIG, serializer);
config.put(ACKS_CONFIG, "all");
return unmodifiableMap(config);
}