client.go
func OptImportSort(sorting bool) ImportOption {
	return func(options *ImportOptions) error {
		// skipSort is expressed negatively because we want to
		// keep sorting enabled by default, so the zero value should
		// be that default behavior. The client option expresses it
		// positively because that's easier for API users.
		options.skipSort = !sorting
		return nil
	}
}
func OptImportSort(sorting bool) ImportOption {
	return func(options *ImportOptions) error {
		// skipSort is expressed negatively because we want to
		// keep sorting enabled by default, so the zero value should
		// be that default behavior. The client option expresses it
		// positively because that's easier for API users.
		options.skipSort = !sorting
		return nil
	}
}
// OptImportSort tells the importer whether or not to sort batches of records, on
// by default. Sorting imposes some performance cost, especially on data that's
// already sorted, but dramatically improves performance in pathological
// cases. It is enabled by default because the pathological cases are awful,
// and the performance hit is comparatively small, but the performance cost can
// be significant if you know your data is sorted.