code: func NewRealtimeStatsClient() *RTSClient {
  	c, err := NewClientForEndpoint(os.Getenv(APIKeyEnvVar), RealtimeStatsEndpoint)
  	if err != nil {
  		panic(err)
  	}
  	return &RTSClient{client: c}
  }
docs: // NewRealtimeStatsClient instantiates a new Fastly API client for the realtime stats.
  // This function requires the environment variable `FASTLY_API_KEY` is set and contains
  // a valid API key to authenticate with Fastly.