Goroutines

package main

import (
    "fmt"
    "time"
)

func f(from string) {
    for i := 0; i < 3; i++ {
        fmt.Println(from, ":", i)
    }
}

func main() {
    // Calling f synchronously.
    f("direct")

    // To invoke this function in a goroutine, use go f(s).
    // This new goroutine will execute concurrently with the calling one.
    go f("goroutine")

    // You can also start a goroutine for an anonymous function call.
    go func(msg string) {
        fmt.Println(msg)
    }("going")

    // Our two function calls are running asynchronously in separate goroutines now.
    // Wait for them to finish (for a more robust approach, use a WaitGroup).
    time.Sleep(time.Second)
    fmt.Println("done")
}