httpclient/http.go
func filterHeaders(
	dumpFormat Format,
	hiddenHeaders map[string]bool,
	headers http.Header,
	iterator headerIterator) {

	for k, v := range headers {
		if !dumpFormat.IsVerbose() {
			if _, ok := hiddenHeaders[k]; ok {
				continue
			}
		}
		iterator(k, v)
	}
}
func filterHeaders(
	dumpFormat Format,
	hiddenHeaders map[string]bool,
	headers http.Header,
	iterator headerIterator) {

	for k, v := range headers {
		if !dumpFormat.IsVerbose() {
			if _, ok := hiddenHeaders[k]; ok {
				continue
			}
		}
		iterator(k, v)
	}
}
// filterHeaders iterates through the headers skipping hidden headers unless DumpFormat is Verbose.
// It calls the given iterator for each header name/value pair. The values are serialized as
// strings.