The command shows a list of all the usernames of the currently configured users in the Redis ACL system. *返回值 An array of strings. *例子 > ACL USERS 1) "anna" 2) "antirez" 3) "default" 可用版本>= 6.0.0. 时间复杂度: O(N)。其中N是已配置的用户数。