docs: clarify CPU-bound tasks on Tokio
//! ```
//!
//! If your code is CPU-bound and you wish to limit the number of threads used
-//! to run it, you should run it on another thread pool such as [rayon]. You
-//! can use an [`oneshot`] channel to send the result back to Tokio when the
-//! rayon task finishes.
+//! to run it, you should use a separate thread pool dedicated to CPU bound tasks.
+//! For example, you could consider using the [rayon] library for CPU-bound
+//! tasks. It is also possible to create an extra Tokio runtime dedicated to
+//! CPU-bound tasks, but if you do this, you should be careful that the extra
+//! runtime runs _only_ CPU-bound tasks, as IO-bound tasks on that runtime
+//! will behave poorly.
+//!
+//! Hint: If using rayon, you can use a [`oneshot`] channel to send the result back
+//! to Tokio when the rayon task finishes.
//!
//! [rayon]: https://docs.rs/rayon
//! [`oneshot`]: crate::sync::oneshot
