No it's not. You can set up async runtimes that run on a single thread and service thousands of long-running connections with slow clients. Tokio, the most popu

No it's not. You can set up async runtimes that run on a single thread and service thousands of long-running connections with slow clients. Tokio, the most popular Rust async runtime, starts one thread per CPU core by default, and you can have thousands of tasks running on just a few OS threads.