src/Web/Sessions/Session.php
public function removeAll()
    {
        $this->open();
        $data = $this->data;
        foreach (array_keys($data) as $key) {
            unset($data[$key]);
        }
        $this->data = $data;
        return $this->writeSession();
    }
public function removeAll()
    {
        $this->open();
        $data = $this->data;
        foreach (array_keys($data) as $key) {
            unset($data[$key]);
        }
        $this->data = $data;
        return $this->writeSession();
    }
Removes all session variables.
@return PromiseInterface with bool when write process ends