code: func buildHeader(headerList []v1.HTTPHeader) http.Header {
  	headers := make(http.Header)
  	for _, header := range headerList {
  		headers[header.Name] = append(headers[header.Name], header.Value)
  	}
  	return headers
  }
docs: // buildHeaderMap takes a list of HTTPHeader <name, value> string
  // pairs and returns a populated string->[]string http.Header map.