Yeah this is true, typically you want to keep blocking functions outside this. By default, core.async allocates as many threads as cores in your CPU. In additi

Yeah this is true, typically you want to keep blocking functions outside this. By default, core.async allocates as many threads as cores in your CPU. In addition to this, I personally find core.async to deal poorly with flow control (e.g. slow subscribers slowing down the entire flow for every subscriber), and seems to not have a lot of telemetry / it’s difficult to find out what’s going on in the thread pool behind it. I’ve personally settled on Zach Tellman’s Manifold library, which provides a much more sane abstraction and is fully compatible with core.async. For some addition thought and material on these topics, I highly recommend watching this talk by Zach, “Everything Will Flow” https://youtu.be/1bNOO3xxMc0 https://youtu.be/1bNOO3xxMc0