Avoid leaking tickers

In Go 1.22 and earlier, a ticker needs to be explicitly stopped
when it's no longer useful in order to avoid a resource leak.
In Go 1.23 and later, an orphaned ticker will eventually be
garbage collected, but it's still more thrifty to stop it early.

examples/data-channels/main.go

@@ -70,7 +70,9 @@ func main() {
 		d.OnOpen(func() {
 			fmt.Printf("Data channel '%s'-'%d' open. Random messages will now be sent to any connected DataChannels every 5 seconds\n", d.Label(), d.ID())
 
-			for range time.NewTicker(5 * time.Second).C {
+			ticker := time.NewTicker(5 * time.Second)
+			defer ticker.Stop()
+			for range ticker.C {
 				message, sendErr := randutil.GenerateCryptoRandomString(15, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
 				if sendErr != nil {
 					panic(sendErr)