Какое назначение у конструкции Wait Group в синхронизации горутин?

WaitGroup in Go is used for synchronizing multiple goroutines. It allows the main goroutine (or any other) to wait for a group of goroutines to finish.

The main purpose of WaitGroup is to track the number of active goroutines and block execution until all of them have completed.

Example usage:

var wg sync.WaitGroup

wg.Add(3) // expecting 3 goroutines to finish

for i := 0; i < 3; i++ {
    go func(id int) {
        defer wg.Done() // signal goroutine completion
        // goroutine work
        fmt.Println("Goroutine", id, "completed")
    }(i)
}

wg.Wait() // wait until counter reaches 0
fmt.Println("All goroutines are finished")

Thus, WaitGroup helps coordinate parallel execution and ensures that the program does not continue until all necessary goroutines have finished.