client.go
func OptImportClear(clear bool) ImportOption {
	return func(options *ImportOptions) error {
		options.clear = clear
		return nil
	}
}
func OptImportClear(clear bool) ImportOption {
	return func(options *ImportOptions) error {
		options.clear = clear
		return nil
	}
}
// OptImportClear sets clear import, which clears bits instead of setting them.