code: public static Single<Long> remove(CacheConfigBean cacheConfigBean, String key, Object member) {
          Set<Object> members = new HashSet<>();
          members.add(member);
          return removes(cacheConfigBean, key, members);
      }
docs: remove the given element from the cache set
  
  @param cacheConfigBean datasource configuration
  @param key             the key
  @param member          element to be removed
  @return the removed elements count