test(gateway): measure qualification wire capacity

gateway/gateway_test.go

@@ -940,12 +940,20 @@ func (c *independentGatewayClient) ReceiveFrame(ctx context.Context) (Frame, err
 }
 
 func (c *independentGatewayClient) ReceiveMedia(ctx context.Context) ([]byte, error) {
+	return c.receiveMedia(ctx, nil)
+}
+
+func (c *independentGatewayClient) receiveMedia(ctx context.Context, observe func(time.Time, int)) ([]byte, error) {
 	for {
 		data, err := c.connection.ReceiveDatagram(ctx)
 		if err != nil {
 			return nil, err
 		}
-		payload, complete, err := c.media.Add(data, time.Now())
+		receivedAt := time.Now()
+		if observe != nil {
+			observe(receivedAt, len(data))
+		}
+		payload, complete, err := c.media.Add(data, receivedAt)
 		if err != nil {
 			return nil, err
 		}