Available in: Redis Stack
Time complexity: O(k * n), where k is the number of hash functions and n is the number of items
Determines if one or more items may exist in the filter or not.
 - for each item where "1" value means the corresponding item may exist in the filter, and a "0" value means it does not exist in the filter.
redis> BF.MEXISTS bf item1 item_new 1) (integer) 1 2) (integer) 0