http/httpheader.go
func (s *HttpHeader) SetWriter(h http.Header) *HttpHeader {
	h.Set(s.Name, s.Value)
	return s
}
func (s *HttpHeader) SetWriter(h http.Header) *HttpHeader {
	h.Set(s.Name, s.Value)
	return s
}
// SetWriter sets HTTP header, as defined by current instance, to ResponseWriter
// Header.