code: func NewStatsFetcher(logger *log.Logger, pool *pool.ConnPool, datacenter string) *StatsFetcher {
  	return &StatsFetcher{
  		logger:     logger,
  		pool:       pool,
  		datacenter: datacenter,
  		inflight:   make(map[string]struct{}),
  	}
  }
docs: // NewStatsFetcher returns a stats fetcher.