Rust: What is the difference between sync::mpsc and tokio::sync::mpsc?

sync::mpsc — blocking channel. tokio::sync::mpsc — async channel.

sync::mpsc:

• Blocking.
• Blocks thread.
• For sync code.

tokio::sync::mpsc:

• Async.
• Non-blocking.
• For async code.

1// Blocking
2use std::sync::mpsc;
3let (tx, rx) = mpsc::channel();
4tx.send("hello").unwrap();
5
6// Async
7use tokio::sync::mpsc;
8let (tx, mut rx) = mpsc::channel(32);
9tx.send("hello").await.unwrap();

Key: std for blocking, tokio for async.