void reenqueued(long now) {
        attempts.getAndIncrement();
        lastAttemptMs = Math.max(lastAppendTime, now);
        lastAppendTime = Math.max(lastAppendTime, now);
        retry = true;
    }
A callback and the associated FutureRecordMetadata argument to pass to it.
clients/src/main/java/org/apache/kafka/clients/producer/internals/ProducerBatch.java