out of curiosity, does it use core.async or manifold for concurrency? (and what are the tradeoffs)
Part of that is because Jepsen isn't hyper-concurrent. Most concurrency errors manifest in just a handful of client threads, and the JVM will run ~10K threads without too many issues.
Another part is that I spend a lot of time debugging and profiling. Core.async turns stacktraces into Swiss cheese--it has to, to perform its implicit continuation-passing magic. But that can make it really hard to figure out Who Called What When, and Why Is This Process Slow. Standard blocking IO calls are also something that my profiler (YourKit) can analyze well.
Finally, I invest a lot of time into tuning Jepsen for speed, and manage the handoff of data between threads carefully. In a system where actors were handing off state constantly core.async would be a bigger help, but there's really only a couple shapes for concurrent handoff in Jepsen, and they're addressed by either j.u.c. queues, forkjoin-style structured concurrency, or Weird Transactional Threadpool stuff.
For a little more on this, take a look at https://github.com/aphyr/dom-top or https://github.com/jepsen-io/history/blob/main/src/jepsen/hi...
(As an aside: Missionary is a higher-level, more recent option in this area.)
Missionary looks very cool, but I don't think anyone understands how to use it. Other than Electric/Rama (from the same people) I haven't been able to find any projects that use it on Github
The tutorials are fairly accessible: https://cljdoc.org/d/missionary/missionary/b.33/doc/readme/t...
In a recent London Clojurians talk, the author Leo Noel explained Electric can be thought of as a frontend for Missionary. Rama is by a different team (RPL), but agreed, their philosophies are similar.
I'll be honest, part of the problem is I don't work in the web space. So I don't care for (or completely understand) the things they're looking to solve (ex: server/client sync issues). I just want to have simpler state-management and have changes propagate across my program in a way that makes my life easier :) (think like a "notebook" where you update values and everything gets reevaluated where-needed)