I didn’t mean to imply that Jetstream is slow. It’s just that I did my benchmarks without it. On a local PC, with 10 KiB messages sent (synchronously) in a loop, I could transfer 3.2 GiB over 5 seconds with 0.2 nanoseconds latency. Performing the same test with RabbitMQ, I got even better throughput out of the box, but way worse latency.

Those numbers are for server 2.9.6 and .NET client 1.0.8.