Tokio’s channel primitives

Tokio provides a number of channels, each serving a different purpose.

• mpsc: multi-producer, single-consumer channel. Many values can be sent.
• oneshot: single-producer, single consumer channel. A single value can be sent.
• broadcast: multi-producer, multi-consumer. Many values can be sent. Each receiver sees every value.
• watch: single-producer, multi-consumer. Many values can be sent, but no history is kept. Receivers only see the most recent value.

If you need a multi-producer multi-consumer channel where only one consumer sees each message, you can use the async-channel crate. There are also channels for use outside of asynchronous Rust, such as std::sync::mpsc and crossbeam::channel. These channels wait for messages by blocking the thread, which is not allowed in asynchronous code.

In this section, we will use mpsc and oneshot. The other types of message passing channels are explored in later sections. The full code from this section is found here.