Update multireader.go

more description

multireader.go

@@ -15,13 +15,13 @@ func tickReader(sem chan struct{}, ticker *time.Ticker, s string) io.Reader {
 	r, w := io.Pipe()
 	go func() {
 		for {
-			sem <- struct{}{}
+			sem <- struct{}{} // acquire a ticket, possibly waiting for it
 			select {
 			case t := <-ticker.C:
 				fmt.Fprintf(w, "%s with %v\n", s, t)
 			default: // try to comment this and then run :)
 			}
-			<-sem
+			<-sem // add a ticket to the semaphore 
 		}
 	}()
 	return r
@@ -45,7 +45,10 @@ func tickToReader(semaphore chan struct{}, v tick) (io.Reader, error) {
 func main() {
 	var (
 		wg        sync.WaitGroup
-		semaphore = make(chan struct{}, 1)
+		semaphore = make(
+			chan struct{}, 
+			1, // only one goroutine can do its thing
+		)
 	)
 
 	var tickers = []tick{