[#176] morph: Resolve funlen linter

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/morph/client/notifications.go

@@ -240,37 +240,7 @@ func (c *Client) restoreSubscriptions(cli *rpcclient.WSClient, endpoint string,
 	notificationRcv := make(chan *state.ContainedNotificationEvent)
 	notaryReqRcv := make(chan *result.NotaryRequestEvent)
 
-	// neo-go WS client says to _always_ read notifications
+	c.startListen(stopCh, blockRcv, notificationRcv, notaryReqRcv, background)
-	// from its channel. Subscribing to any notification
-	// while not reading them in another goroutine may
-	// lead to a dead-lock, thus that async side notification
-	// listening while restoring subscriptions
-	go func() {
-		var e any
-		var ok bool
-
-		for {
-			select {
-			case <-stopCh:
-				return
-			case e, ok = <-blockRcv:
-			case e, ok = <-notificationRcv:
-			case e, ok = <-notaryReqRcv:
-			}
-
-			if !ok {
-				return
-			}
-
-			if background {
-				// background client (test) switch, no need to send
-				// any notification, just preventing dead-lock
-				continue
-			}
-
-			c.routeEvent(e)
-		}
-	}()
 
 	if background {
 		c.switchLock.RLock()
@@ -334,6 +304,42 @@ func (c *Client) restoreSubscriptions(cli *rpcclient.WSClient, endpoint string,
 	return si, true
 }
 
+func (c *Client) startListen(stopCh <-chan struct{}, blockRcv <-chan *block.Block,
+	notificationRcv <-chan *state.ContainedNotificationEvent, notaryReqRcv <-chan *result.NotaryRequestEvent, background bool) {
+	// neo-go WS client says to _always_ read notifications
+	// from its channel. Subscribing to any notification
+	// while not reading them in another goroutine may
+	// lead to a dead-lock, thus that async side notification
+	// listening while restoring subscriptions
+
+	go func() {
+		var e any
+		var ok bool
+
+		for {
+			select {
+			case <-stopCh:
+				return
+			case e, ok = <-blockRcv:
+			case e, ok = <-notificationRcv:
+			case e, ok = <-notaryReqRcv:
+			}
+
+			if !ok {
+				return
+			}
+
+			if background {
+				// background client (test) switch, no need to send
+				// any notification, just preventing dead-lock
+				continue
+			}
+
+			c.routeEvent(e)
+		}
+	}()
+}
+
 func copySubsMap(m map[util.Uint160]string) map[util.Uint160]string {
 	newM := make(map[util.Uint160]string, len(m))
 	for k, v := range m {