typedef struct _DRIVER_EXTENSION
{
    DRIVER_OBJECT *DriverObject;
    long (*AddDevice)(DRIVER_OBJECT *, DEVICE_OBJECT *);
    unsigned long Count;
    UNICODE_STRING ServiceKeyName;
    IO_CLIENT_EXTENSION *ClientDriverExtension;
    FS_FILTER_CALLBACKS *FsFilterCallbacks;
} DRIVER_EXTENSION, *PDRIVER_EXTENSION;