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: clearsign.go
    path of file: ./repos/gitkube/vendor/golang.org/x/crypto/openpgp/clearsign
    
    the code of the file until where you have to start completion: // Copyright 2012 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 clearsign generates and processes OpenPGP, clear-signed data. See
// RFC 4880, section 7.
//
// Clearsigned messages are cryptographically signed, but the contents of the
// message are kept in plaintext so that it can be read without special tools.
package clearsign // import "golang.org/x/crypto/openpgp/clearsign"

import (
	"bufio"
	"bytes"
	"crypto"
	"fmt"
	"hash"
	"io"
	"net/textproto"
	"strconv"

	"golang.org/x/crypto/openpgp/armor"
	"golang.org/x/crypto/openpgp/errors"
	"golang.org/x/crypto/openpgp/packet"
)

// A Block represents a clearsigned message. A signature on a Block can
// be checked by passing Bytes into openpgp.CheckDetachedSignature.
type Block struct {
	Headers          textproto.MIMEHeader // Optional message headers
	Plain
    
func EncodeMulti(w io.Writer, privateKeys []*packet.PrivateKey, config *packet.Config) (plaintext io.WriteCloser, err error) {
	for _, k := range privateKeys {
		if k.Encrypted {
			return nil, errors.InvalidArgumentError(fmt.Sprintf("signing key %s is encrypted", k.KeyIdString()))
		}
	}

	hashType := config.Hash()
	name := nameOfHash(hashType)
	if len(name) == 0 {
		return nil, errors.UnsupportedError("unknown hash type: " + strconv.Itoa(int(hashType)))
	}

	if !hashType.Available() {
		return nil, errors.UnsupportedError("unsupported hash type: " + strconv.Itoa(int(hashType)))
	}
	var hashers []hash.Hash
	var ws []io.Writer
	for range privateKeys {
		h := hashType.New()
		hashers = append(hashers, h)
		ws = append(ws, h)
	}
	toHash := io.MultiWriter(ws...)

	buffered := bufio.NewWriter(w)
	// start has a \n at the beginning that we don't want here.
	if _, err = buffered.Write(start[1:]); err != nil {
		return
	}
	if err = buffered.WriteByte(lf); err != nil {
		return
	}
	if _, err = buffered.WriteString("Hash: "); err != nil {
		return
	}
	if _, err = buffered.WriteString(name); err != nil {
		return
	}
	if err = buffered.WriteByte(lf); err != nil {
		return
	}
	if err = buffered.WriteByte(lf); err != nil {
		return
	}

	plaintext = &dashEscaper{
		buffered: buffered,
		hashers:  hashers,
		hashType: hashType,
		toHash:   toHash,

		atBeginningOfLine: true,
		isFirstLine:       true,

		byteBuf: make([]byte, 1),

		privateKeys: privateKeys,
		config:      config,
	}

	return
}