src/core/Session.php
public function start(?string $name = null, ?string $sessionId = null): string
    {
        if (!$this->isStarted()) {
            if (!is_null($name)) {
                $this->setName($name);
            }
            @session_start($sessionId);
        };
        return $this->getId();
    }
public function start(?string $name = null, ?string $sessionId = null): string
    {
        if (!$this->isStarted()) {
            if (!is_null($name)) {
                $this->setName($name);
            }
            @session_start($sessionId);
        };
        return $this->getId();
    }
It inits the data of new session or continues the current session.
@param string $name The optional name of session, it has higher priority
than the $iSess parameter.
@param string $sessionId The optional session ident. It ignored if the $sSessName
parameter was passed.
@return string The id of current session.