src/MockStorage.php
public function unlock(string $sessionIdentifier): void
    {
        $index = array_search($sessionIdentifier, self::$lockedIdentifiers);

        if ($index !== false) {
            unset(self::$lockedIdentifiers[$index]);
        }
    }
public function unlock(string $sessionIdentifier): void
    {
        $index = array_search($sessionIdentifier, self::$lockedIdentifiers);

        if ($index !== false) {
            unset(self::$lockedIdentifiers[$index]);
        }
    }
Asks the drive to unlock the session storage

@param string $sessionIdentifier The session identifier to be unlocked
@return void