src/StreamWrapper.php
public static function has($file)
    {
        if ($file instanceof StreamInterface) {
            $file = 'spiral://' . spl_object_hash($file);
        }

        return isset(self::$uris[$file]);
    }
public static function has($file)
    {
        if ($file instanceof StreamInterface) {
            $file = 'spiral://' . spl_object_hash($file);
        }

        return isset(self::$uris[$file]);
    }
Check if given uri or stream has been allocated.

@param string|StreamInterface $file
@return bool