// bother trying to roundtrip it.
		if len(files) == 0 {
			return
		}

		w := NewWriter(io.Discard)
		for _, f := range files {
			ww, err := w.CreateHeader(f.header)
			if err != nil {
				t.Fatalf("unable to write previously parsed header: %s", err)
			}
			if _, err := ww.Write(f.content); err != nil {
				t.Fatalf("unable to write previously parsed content: %s", err)
			}
		}

		if err := w.Close(); err != nil {

		frame = ws.NewFrame(op, fin, p)
	}

	return ww.writeFrame(w, frame)
}

// writeFrame writes frame binary representation into w.
func (ww *wsWriter) writeFrame(w io.Writer, f ws.Frame) error {
	const (
		bit0  = 0x80
		len7  = int64(125)
		len16 = int64(^(uint16(0)))
		len64 = int64(^(uint64(0)) >> 1)
	)

	bts := ww.tmp[:]
	if f.Header.Fin {
		bts[0] |= bit0
	}