src/BTR/RedisObjects/RedisSet.php
public function add($member, ...$members): int
    {
        array_unshift($members, $member);

        return $this->redis->sadd($this->key, $this->serializeArray($members));
    }
public function add($member, ...$members): int
    {
        array_unshift($members, $member);

        return $this->redis->sadd($this->key, $this->serializeArray($members));
    }
@param mixed $member     First member that's added to the list.
@param mixed ...$members More members to add.

@return int Amount of newly added members in set.