n = 2

	case f.Header.Length <= len16:
		bts[1] = 126
		binary.BigEndian.PutUint16(bts[2:4], uint16(f.Header.Length))
		n = 4

	case f.Header.Length <= len64:
		bts[1] = 127
		binary.BigEndian.PutUint64(bts[2:10], uint64(f.Header.Length))
		n = 10

	default:
		return ws.ErrHeaderLengthUnexpected
	}

	if f.Header.Masked {
		bts[1] |= bit0