type disconnectReader struct {
	r  io.Reader
	mu sync.Mutex
}

func (d *disconnectReader) Read(p []byte) (n int, err error) {
	d.mu.Lock()
	defer d.mu.Unlock()
	if d.r != nil {
		return d.r.Read(p)
	}
	return 0, errors.New("reader closed")
}

func (d *disconnectReader) Close() error {
	d.mu.Lock()
	d.r = nil
	d.mu.Unlock()
	return nil
}

	if err := DB.Transaction(func(tx *gorm.DB) error {
		return nil
	}); err == nil {
		t.Errorf("should returns error when commit with closed conn, got error %v", err)
	}

	if err := DB.Session(&gorm.Session{PrepareStmt: true}).Transaction(func(tx *gorm.DB) error {
		return nil
	}); err == nil {
		t.Errorf("should returns error when commit with closed conn, got error %v", err)
	}
}

// The remaining payload and versions are returned.
func checkXL2V1(buf []byte) (payload []byte, major, minor uint16, e error) {
	if len(buf) <= 8 {
		return payload, 0, 0, fmt.Errorf("xlMeta: no data")
	}

	if !bytes.Equal(buf[:4], xlHeader[:]) {
		return payload, 0, 0, fmt.Errorf("xlMeta: unknown XLv2 header, expected %v, got %v", xlHeader[:4], buf[:4])
	}

	if bytes.Equal(buf[4:8], []byte("1   ")) {

		t.Fatalf("should raise error when create users without languages reference")
	}

	if err := DB.Create(&user.Languages).Error; err != nil {
		t.Fatalf("no error should happen when create languages, but got %v", err)
	}

	if err := DB.Omit("Languages.*").Create(&user).Error; err != nil {
		t.Fatalf("no error should happen when create user when languages exists, but got %v", err)
	}

	if err := DB.Model(&User{}).Where("name like ?", "distinct%").Count(&count).Error; err != nil || count != 5 {
		t.Errorf("failed to query users count, got error: %v, count: %v", err, count)
	}

	if err := DB.Model(&User{}).Distinct("name").Where("name like ?", "distinct%").Count(&count).Error; err != nil || count != 3 {
		t.Errorf("failed to query users count, got error: %v, count %v", err, count)
	}

			if testCase.expectedError.Error() != actualErr.Error() {
				t.Errorf("Test %d: %s: Expected to fail with error \"%s\", but instead failed with error \"%s\" instead.", i+1, instanceType, testCase.expectedError.Error(), actualErr.Error())
			}
		}
		// Test passes as expected, but the output values are verified for correctness here.
		if actualErr == nil && testCase.shouldPass {

		t.Errorf("failed to find item parent, got error: %v", err)
	}
	if len(parents) != 1 {
		t.Errorf("expected %d parents, got %d", 1, len(parents))
	}

	// test delete
	if err := tx.Model(&item).Association("ItemParent").Unscoped().Delete(&parents); err != nil {
		t.Errorf("failed to delete item parent, got error: %v", err)
	}
	if err := tx.Find(&parents).Error; err != nil {

	if info.Free > info.Total {
		return info, fmt.Errorf("detected free space (%d) > total drive space (%d), fs corruption at (%s). please run 'fsck'", info.Free, info.Total, path)
	}
	info.Used = info.Total - info.Free
	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")

	Name() string
	SendFromStore(key Key) error
}

// Store - Used to persist items.
type Store[I any] interface {
	Put(item I) (Key, error)
	PutMultiple(item []I) (Key, error)
	Get(key Key) (I, error)
	GetMultiple(key Key) ([]I, error)
	GetRaw(key Key) ([]byte, error)
	PutRaw(b []byte) (Key, error)
	Len() int
	List() []Key
	Del(key Key) error
	Open() error
	Delete() error
}

	}
	if len(data) <= 4 {
		return fmt.Errorf("%s: no data", ri.JobType)
	}
	// Read header
	switch binary.LittleEndian.Uint16(data[0:2]) {
	case format:
	default:
		return fmt.Errorf("%s: unknown format: %d", ri.JobType, binary.LittleEndian.Uint16(data[0:2]))
	}
	switch binary.LittleEndian.Uint16(data[2:4]) {
	case version:
	default: