Rust: What is the difference between std::future and tokio::time::sleep?

std::future — core future trait. tokio::time::sleep — async sleep.

std::future:

• Future trait.
• Core abstraction.
• Runtime-agnostic.

tokio::time::sleep:

• Async sleep.
• Tokio-specific.
• For async code.

1use std::future::Future;
2
3fn my_future() -> impl Future<Output = i32> {
4    async { 42 }
5}
6
7use tokio::time::{sleep, Duration};
8sleep(Duration::from_secs(1)).await;

Key: std::future for core, tokio for specific operations.