You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: public_key_v3.go
    path of file: ./repos/lazygit/vendor/golang.org/x/crypto/openpgp/packet
    
    the code of the file until where you have to start completion: // Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package pack
    
func (pk *PublicKeyV3) serializeWithoutHeaders(w io.Writer) (err error) {
	var buf [8]byte
	// Version 3
	buf[0] = 3
	// Creation time
	t := uint32(pk.CreationTime.Unix())
	buf[1] = byte(t >> 24)
	buf[2] = byte(t >> 16)
	buf[3] = byte(t >> 8)
	buf[4] = byte(t)
	// Days to expire
	buf[5] = byte(pk.DaysToExpire >> 8)
	buf[6] = byte(pk.DaysToExpire)
	// Public key algorithm
	buf[7] = byte(pk.PubKeyAlgo)

	if _, err = w.Write(buf[:]); err != nil {
		return
	}

	switch pk.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
		return writeMPIs(w, pk.n, pk.e)
	}
	return errors.InvalidArgumentError("bad public-key algorithm")
}