When you starting writing applications in Go that leverage goroutines, you start hitting scenarios where you need to block the execution of certain parts of your code base, until these goroutines have successfully executed.
WaitGroups essentially allow us to tackle this problem by blocking until any goroutines within that WaitGroup have successfully executed.
We first call .Add(1) (before execute your goroutines) on our WaitGroup to set the number of goroutines we want to wait for, and subsequently, we call .Done() within any goroutines to signal the end of its execution.