Consumer lagging

[Umbralith]

I have 1 producer producing ~20k m/s and 1 consumer trying to consumer them all without falling behind. I'm using 16 threads on the handler and I set the max-in-flight to be 2500 and it seems it's capping messages processed at ~7k m/s. I've been trying to play with the threads, max-in-flight, and even starting up multiple consumers in the same app and nothing seems to help. Any suggestions or ideas on what could be wrong? Not entirely sure how I should think of the threads and max-in-flight as the library does not support async/await so maybe it's an issue with thread starvation?

Processing messages is not CPU bound as the messages get processed in ~0.002ms