template.go
func (t *Template) ExecuteString(m map[string]interface{}) string {
	return t.ExecuteFuncString(func(w io.Writer, tag string) (int, error) { return stdTagFunc(w, tag, m) })
}
func (t *Template) ExecuteString(m map[string]interface{}) string {
	return t.ExecuteFuncString(func(w io.Writer, tag string) (int, error) { return stdTagFunc(w, tag, m) })
}
// ExecuteString substitutes template tags (placeholders) with the corresponding
// values from the map m and returns the result.
//
// Substitution map m may contain values with the following types:
//   * []byte - the fastest value type
//   * string - convenient value type
//   * TagFunc - flexible value type
//
// This function is optimized for frozen templates.
// Use ExecuteString for constantly changing templates.