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: encode.go
    path of file: ./repos/alipay
    
    the code of the file until where you have to start completion: package alipay

import (
	"bytes"
	"github.com/smartwalle/nsign"
	"net/url"
	"sort"
	"strings"
)

type Encoder struct {
}

// EncodeValues
// 1、将参数名及其对应的值进行升序排序
// 2、将排序后的参数名及参数名使用等号进行连接，例如：a=10
// 3、将组合之后的参数使用&号进行连接
    
func (encoder *Encoder) EncodeBytes(buffer *bytes.Buffer, data []byte, opts *nsign.SignOptions) ([]byte, error) {
	if data == nil {
		return nil, nil
	}

	if opts.Prefix != "" {
		buffer.WriteString(opts.Prefix)
	}

	buffer.Write(data)

	if opts.Suffix != "" {
		buffer.WriteString(opts.Suffix)
	}

	return buffer.Bytes(), nil
}