Fatal Error: The string is not 64 bit long. PHP 8.2

[waqasalieee]

Fatal error: Uncaught bandwidthThrottle\tokenBucket\storage\StorageException:
The string is not 64 bit long. in \bandwidth-throttle\token-bucket\classes\util\DoublePacker.php: 41

Having this error when applied following code in constructor of ApiController, and tried to use consume:

`function __construct() {

    $this->storage = new FileStorage(__DIR__ . "/api.bucket");
    $this->rate    = new Rate(10, Rate::SECOND);
    $this->bucket  = new TokenBucket(10, $this->rate, $this->storage);
     //Following code executed once, then commented
     //$this->bucket->bootstrap(10);

}`

`protected function checkRateLimit() {

    if (!$this->bucket->consume(1, $seconds)) {
        http_response_code(429);
        header(sprintf("Retry-After: %d", floor($seconds)));
        exit();
    }
    //echo "Continue to API response";
    return true;

}`

I have also noticed FileStorage class is sending blank string to unpack( ) function in Double Packer on line 129.

bandwidthThrottle\tokenBucket\util\DoublePacker: :unpack('')

Please guide what's going wrong here?