return false
		}
		return true
	}

	return false
}

func (t *transferWriter) writeHeader(w io.Writer, trace *httptrace.ClientTrace) error {
	if t.Close && !hasToken(t.Header.get("Connection"), "close") {
		if _, err := io.WriteString(w, "Connection: close\r\n"); err != nil {
			return err
		}
		if trace != nil && trace.WroteHeaderField != nil {

		// mtime precision, reject caching if a file was read that
		// is less than modTimeCutoff old.
		//
		// This is the same strategy used for hashing test inputs.
		// See hashOpen in cmd/go/internal/test/test.go for the
		// corresponding code.
		if info.ModTime().After(cutoff) {
			return cache.ActionID{}, ErrNotIndexed
		}