go - What is the method set of `sync.WaitGroup`?

Question

I have this simple program below

package main

import (
    "fmt"
    "sync"
    "time"
)

var wg sync.WaitGroup

func main() {
    wg.Add(1)

    go func() {
        fmt.Println("starting...")
        time.Sleep(1 * time.Second)
        fmt.Println("done....")
        wg.Done()
    } ()

    wg.Wait()

}

Notice that I use var wg sync.WaitGroup as a value, not a pointer. But the page for the sync package specifies that the Add, Done and Wait function take a *sync.WaitGroup.

Why/How does this work?

Answer 1

Waitting for answers