@Override
  public Object evalsha(final String sha1, final String key, final String params) {
    return execute((jedis) -> jedis.evalsha(sha1, Lists.newArrayList(redisKeyPrefix + key),
        Lists.newArrayList(params)));
  }
Default implementation for {@link JedisTaskExecutor} which is the Jedis wrapper used to access
Redis.

TODO(zheng): support redis cluster.
src/main/java/com/eudemon/ratelimiter/redis/DefaultJedisTaskExecutor.java