search/struct.go
func SaveStruct(src interface{}) ([]Field, error) {
	f, _, err := saveStructWithMeta(src)
	return f, err
}
func SaveStruct(src interface{}) ([]Field, error) {
	f, _, err := saveStructWithMeta(src)
	return f, err
}
// SaveStruct returns the fields from src as a slice of Field.
// src must be a struct pointer.