code: func New(id, location string, interval time.Duration, pool *redis.Pool) *Heartbeater {
  	h := &Heartbeater{
  		ID:       id,
  		Location: location,
  		interval: interval,
  		pool:     pool,
  	}
  	h.Strategy = HashExpireyStrategy{h.MaxAge()}
  
  	return h
  }
docs: // New allocates and returns a pointer to a new instance of a Heartbeater. It
  // takes in the id, location, interval and pool with which to use to create
  // Hearts and Detectors.