Looking at the documentation, I'm not sure if I understand the difference between using close() and flush().
This is the doc for flush()
* Invoking this method makes all buffered records immediately available to send (even if <code>linger.ms</code> is * greater than 0) and blocks on the completion of the requests associated with these records. The post-condition * of <code>flush()</code> is that any previously sent record will have completed (e.g. <code>Future.isDone() == true</code>). * A request is considered completed when it is successfully acknowledged * according to the <code>acks</code> configuration you have specified or else it results in an error.
And the doc for close():
* This method waits up to <code>timeout</code> for the producer to complete the sending of all incomplete requests. * If the producer is unable to complete all requests before the timeout expires, this method will fail * any unsent and unacknowledged records immediately.
Does this mean that:
- If I use close() and there are some records pending in the in-memory buffer, they won't even be attempted (compared to flush, which would attempt to send them)?
- If I use flush(), it might block "forever" if the retries are large? While with close(), I have an upper bound for how long this is going to take?
I suppose if I'm right in 1., a producer with acks=0 would get a confirmation for a record that might not even be attempted to be published if it is "unlucky" enough to be placed in the in-memory queue and immediately after close() is called.
