src/core/Session.php
public function getAll(): array
    {
        $res = [];
        foreach ($this->getKeys() as $key) {
            $res[$key] = $this->get($key);
        }
        return $res;
    }
public function getAll(): array
    {
        $res = [];
        foreach ($this->getKeys() as $key) {
            $res[$key] = $this->get($key);
        }
        return $res;
    }
It returns all session variables as associative array.
@return mixed[]