code: func SetSessionStreamPollPeriod(period time.Duration) HandlerOption {
  	return func(h *Handler) error {
  		if period < 0 {
  			return trace.BadParameter("period should be non zero")
  		}
  		h.sessionStreamPollPeriod = period
  		return nil
  	}
  }
docs: // SetSessionStreamPollPeriod sets polling period for session streams