Right, I think async is bad. We have threads, and operating system level isolation with processes. For the most part, these primitives work fine. My code wasn'

Right, I think async is bad. We have threads, and operating system level isolation with processes. For the most part, these primitives work fine. My code wasn't blocking, but it did a very small amount of computation, locked on what was typically a highly contended (async) lock, and then dispatched a bunch of blocking I/O operations. Each of these turned into a context switch under the hood. There were parts of my code that were computer intensive, but determining that without being able to use my normal tools was a pain, and I had to come up with heuristics of whether or not to dispatch with spawn_blocking, since the call had significant overhead. An abstraction that was meant to simplify program resulted in me spending a lot more time staring at it. I think one difference with Python is that the async implementation doesn't try to hide or abstract I/O away from you. If you're doing I/O, you know you're going to block, and thus you're forced to acknowledge it by spawning it on another thread.