Go WaitGroup

• sync.WaitGroup

A WaitGroup is a counting semaphore that waits for a collection of goroutines to finish. The main goroutine calls Add() to set the number of goroutines to wait for. Then each of the goroutines runs and calls Done() when finished. At the same time, Wait() can be used to block until all goroutines have finished.

Using a waitGroup to wait for goroutines to finish before exiting main(): playground/go/concurrency/waitGroup.go