src/Storage/Memory.php
public function clear($uid = null) {
        if ($uid) {
            unset($this->data[$uid]);
            return;
        }
        $this->data[$uid] = array();
    }
public function clear($uid = null) {
        if ($uid) {
            unset($this->data[$uid]);
            return;
        }
        $this->data[$uid] = array();
    }
Clear datas with $uid key
@param mixed $uid
@return void