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: encodedword.go
    path of file: ./repos/streamdal/apps/server/vendor/gopkg.in/alexcesaro/quotedprintable.v3
    
    the code of the file until where you have to start completion: package quotedprintable

import (
	"bytes"
	"encoding/base64"
	"errors"
	"fmt"
	"io"
	"strings"
	"unicode"
	"unicode/utf8"
)

// A WordEncoder is a RFC 2047 encoded-word encoder.
type WordEncoder byte

const (
	// BEncoding represents Base64
    
func (d *WordDecoder) convert(buf *bytes.Buffer, charset string, content []byte) error {
	switch {
	case strings.EqualFold("utf-8", charset):
		buf.Write(content)
	case strings.EqualFold("iso-8859-1", charset):
		for _, c := range content {
			buf.WriteRune(rune(c))
		}
	case strings.EqualFold("us-ascii", charset):
		for _, c := range content {
			if c >= utf8.RuneSelf {
				buf.WriteRune(unicode.ReplacementChar)
			} else {
				buf.WriteByte(c)
			}
		}
	default:
		if d.CharsetReader == nil {
			return fmt.Errorf("mime: unhandled charset %q", charset)
		}
		r, err := d.CharsetReader(strings.ToLower(charset), bytes.NewReader(content))
		if err != nil {
			return err
		}
		if _, err = buf.ReadFrom(r); err != nil {
			return err
		}
	}
	return nil
}