Panic: just flushed

[crepererum]

Under certain rare circumstances it seems that the BatchProducer panics with just flushed. This is this piece of code here:

rskafka/src/client/producer.rs

Lines 439 to 442 in 7c74d43

	// Flush data
	Self::flush_impl(&mut inner, self.client.as_ref(), self.compression).await;
	extract(&result_slot.now_or_never().expect("just flushed"), tag)

Until now I've seen that only once during benchmarking and once in prod. I'm wondering if now_or_never() is too aggressive.

[tustvold]

Perhaps tokio's operation budgets are kicking in or something? https://tokio.rs/blog/2020-04-preemption

[crepererum]

That might be the case and also explain why you this only happens under certain load situations. I'll see if I can reproduce this somehow.