func Client() *redis.Client {
	return redisClient
}
Client indicates the redis client of the rate limiter.
package redis
import (
	"crypto/sha1"
	"errors"
	"fmt"
	"log"
	"math"
	"time"
	redis "github.com/go-redis/redis"
)
var (
	redisClient *redis.Client
	scriptHash  string
)
const script = `
local tokens_key = KEYS[1]
local timestamp_key = KEYS[2]
local rate = tonumber(ARGV[1])
local capacity = tonumber(ARGV[2])
local now = tonumber(ARGV[3])
local requested = tonumber(ARGV[4])
local fill_time = capacity/rate
local ttl = math.floor(fill_time*2)
local last_tokens = tonumber(redis.call("get", tokens_key))
if last_tokens == nil then
    last_tokens = capacity
end
local last_refreshed = tonumber(redis.call("get", timestamp_key))
if last_refreshed == nil then
    last_refreshed = 0
end
local delta = math.max(0, now-last_refreshed)
local filled_tokens = math.min(capacity, last_tokens+(delta*rate))
local allowed = filled_tokens >= requested
local new_tokens = filled_tokens
if allowed then
    new_tokens = filled_tokens - requested
end
redis.call("setex", tokens_key, ttl, new_tokens)
redis.call("setex", timestamp_key, ttl, now)
return { allowed, new_tokens }
`