code: func New(dialer httpstream.Dialer, ports []string, stopChan <-chan struct{}) (*PortForwarder, error) {
  	if len(ports) == 0 {
  		return nil, errors.New("You must specify at least 1 port")
  	}
  	parsedPorts, err := parsePorts(ports)
  	if err != nil {
  		return nil, err
  	}
  	return &PortForwarder{
  		dialer:   dialer,
  		ports:    parsedPorts,
  		stopChan: stopChan,
  		Ready:    make(chan struct{}),
  	}, nil
  }
docs: // New creates a new PortForwarder.