Tokio's broadcast module is a mpmc messaging queue.

The terms "mpsc" and "mpmc" refer to how the channels can be used. Breaking down the letters, there are two sides to a channel:

• p is producer, or transmitter/sender. This side sends data
• c is consumer, or receiver/reader. This side receives data.

Data only flows one way through a channel. Each side may have a restriction on how many members can be on that side:

• s is single, so this side cannot be cloned. You only have one object that can interact with this side (so only one sender or only one receiver)
• m is multiple, so this side can be cloned. Any number of objects can exist that interact with this side (so a bunch of simultaneous senders or receivers)

A mpsc channel can only have one consumer, so only one thread can receive messages at a time, and it can only receive those messages once.

A mpmc channel can have many consumers, so multiple threads can receive messages at once, and a thread can receive a message multiple times (through multiple receivers).

Both can have multiple simultaneous producers.

Broadcast sends every value to every consumer, mpsc only allows a single consumer to get each value.