Don't leak goroutines everywhere in the ws code

Previous to this past running k6 compiled with the race detector and ws
code will most definetely leak enough goroutines in 10 seconds that it
will stop because of the 8k limit ...
After this it seems to not leak anymore :confetti:

js/modules/k6/ws/ws.go

@@ -247,7 +247,7 @@ func (*WS) Connect(ctx context.Context, url string, args ...goja.Value) (*WSHTTP
 	readErrChan := make(chan error)
 
 	// Wraps a couple of channels around conn.ReadMessage
-	go readPump(conn, readDataChan, readErrChan, readCloseChan)
+	go socket.readPump(readDataChan, readErrChan, readCloseChan)
 
 	// This is the main control loop. All JS code (including error handlers)
 	// should only be executed by this thread to avoid race conditions
@@ -384,7 +384,11 @@ func (s *Socket) SetTimeout(fn goja.Callable, timeoutMs int) {
 	go func() {
 		select {
 		case <-time.After(time.Duration(timeoutMs) * time.Millisecond):
-			s.scheduled <- fn
+			select {
+			case s.scheduled <- fn:
+			case <-s.done:
+				return
+			}
 
 		case <-s.done:
 			return
@@ -402,7 +406,11 @@ func (s *Socket) SetInterval(fn goja.Callable, intervalMs int) {
 		for {
 			select {
 			case <-ticker.C:
-				s.scheduled <- fn
+				select {
+				case s.scheduled <- fn:
+				case <-s.done:
+					return
+				}
 
 			case <-s.done:
 				return
@@ -450,24 +458,35 @@ func (s *Socket) closeConnection(code int) error {
 }
 
 // Wraps conn.ReadMessage in a channel
-func readPump(conn *websocket.Conn, readChan chan []byte, errorChan chan error, closeChan chan int) {
+func (s *Socket) readPump(readChan chan []byte, errorChan chan error, closeChan chan int) {
 	for {
-		_, message, err := conn.ReadMessage()
+		_, message, err := s.conn.ReadMessage()
 		if err != nil {
 			if websocket.IsUnexpectedCloseError(
 				err, websocket.CloseNormalClosure, websocket.CloseGoingAway) {
 				// Report an unexpected closure
-				errorChan <- err
+				select {
+				case errorChan <- err:
+				case <-s.done:
+					return
+				}
 			}
 			code := websocket.CloseGoingAway
 			if e, ok := err.(*websocket.CloseError); ok {
 				code = e.Code
 			}
-			closeChan <- code
+			select {
+			case closeChan <- code:
+			case <-s.done:
+			}
 			return
 		}
 
-		readChan <- message
+		select {
+		case readChan <- message:
+		case <-s.done:
+			return
+		}
 	}
 }
 

js/modules/k6/ws/ws_test.go

@@ -581,7 +581,8 @@ func TestReadPump(t *testing.T) {
 			msgChan := make(chan []byte)
 			errChan := make(chan error)
 			closeChan := make(chan int)
-			go readPump(conn, msgChan, errChan, closeChan)
+			s := &Socket{conn: conn}
+			go s.readPump(msgChan, errChan, closeChan)
 
 		readChans:
 			for {