speedbump.go
func (r *RateLimiter) Has(id string) (bool, error) {
	hash := r.hasher.Hash(id)
	return r.redisClient.Exists(hash).Result()
}
func (r *RateLimiter) Has(id string) (bool, error) {
	hash := r.hasher.Hash(id)
	return r.redisClient.Exists(hash).Result()
}
// Has returns whether the rate limiter has seen a request for a specific id
// during the current period.