Yes, but async Rust is basically built on tokio's runtime, which is what most the big async libraries depend on, like hyper/axum/tokio etc. And tokio is a threa

Yes, but async Rust is basically built on tokio's runtime, which is what most the big async libraries depend on, like hyper/axum/tokio etc. And tokio is a thread-per-core work-stealing architecture, which requires Send + Sync bounds everywhere. You can avoid them if you depend on tokio-proper, but it's more icky when building on something like axum, where your application handlers also require these bounds. A good article on this: https://emschwartz.me/async-rust-can-be-a-pleasure-to-work-with-without-send-sync-static/ https://emschwartz.me/async-rust-can-be-a-pleasure-to-work-w...