Use the full power of closure.

Use the full power of closure by accepting the parameters to anonymous function being run by goroutine.

examples/waitgroups/waitgroups.go

@@ -29,19 +29,16 @@ func main() {
 	// counter for each.
 	for i := 1; i <= 5; i++ {
 		wg.Add(1)
-		// Avoid re-use of the same `i` value in each goroutine closure.
-		// See [the FAQ](https://golang.org/doc/faq#closures_and_goroutines)
-		// for more details.
-		i := i
 		
 		// Wrap the worker call in a closure that makes sure to tell
 		// the WaitGroup that this worker is done. This way the worker
 		// itself does not have to be aware of the concurrency primitives
 		// involved in its execution.
-		go func() {
+		go func(i int) {
 			defer wg.Done()
 			worker(i)
-		}()
+		// use the incremental value of i in each different goroutine.
+		}(i)
 	}
 
 	// Block until the WaitGroup counter goes back to 0;