What is the difference when comparing asynchronous and multithreading?

Asynchrony and multithreading are different concepts, although they often intersect:

• Multithreading is the execution of multiple threads simultaneously, usually on different CPU cores. Each thread can run in parallel, which requires synchronization and state management.

• Asynchrony is a way of organizing code where operations, such as input/output, do not block the execution of the program. Instead of waiting for a result, the program continues working and receives a notification upon completion later.

In Go, for example, asynchrony is achieved through goroutines and channels, which can operate in one or multiple threads, but the main goal is to avoid blocking execution and to use resources efficiently.

Example in Go:

func fetchData() {
    go func() {
        // asynchronous operation
        data := getDataFromNetwork()
        fmt.Println(data)
    }()
    fmt.Println("Request sent, continuing work")
}

Here, go launches a goroutine — a lightweight thread that allows asynchronous task execution.