wsReader := wsutil.Reader{
		Source:          conn,
		State:           c.side,
		CheckUTF8:       true,
		SkipHeaderCheck: false,
		OnIntermediate:  controlHandler,
	}
	readDataInto := func(dst []byte, s ws.State, want ws.OpCode) ([]byte, error) {
		dst = dst[:0]
		for {
			hdr, err := wsReader.NextFrame()
			if err != nil {
				return nil, err
			}
			if hdr.OpCode.IsControl() {