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: renderer.go
    path of file: ./repos/scan4all/vendor/github.com/yuin/goldmark/renderer
    
    the code of the file until where you have to start completion: // Package renderer renders the given AST to certain formats.
package renderer

import (
	"bufio"
	"io"
	"sync"

	"github.com/yuin/goldmark/ast"
	"github.com/yuin/goldmark/util"
)

// A Config struct is a data structure that holds configuration of the Renderer.
type Config struct {
	Options       map[OptionName]interface{}
	NodeRenderers util.PrioritizedSlice
}

// NewConfig returns a new Config.
func NewConfig() *Config {
	return &Config{
		Options:       map[OptionName]interface{}{},
		NodeRenderers: util.PrioritizedSlice{},
	}
}

// An OptionName is a name of the option.
type OptionName string

// An Option interface is a functional option type for the Renderer.
type Option interface {
	SetConfig(*Config)
}

type withNod
    
func (r *renderer) Render(w io.Writer, source []byte, n ast.Node) error {
	r.initSync.Do(func() {
		r.options = r.config.Options
		r.config.NodeRenderers.Sort()
		l := len(r.config.NodeRenderers)
		for i := l - 1; i >= 0; i-- {
			v := r.config.NodeRenderers[i]
			nr, _ := v.Value.(NodeRenderer)
			if se, ok := v.Value.(SetOptioner); ok {
				for oname, ovalue := range r.options {
					se.SetOption(oname, ovalue)
				}
			}
			nr.RegisterFuncs(r)
		}
		r.nodeRendererFuncs = make([]NodeRendererFunc, r.maxKind+1)
		for kind, nr := range r.nodeRendererFuncsTmp {
			r.nodeRendererFuncs[kind] = nr
		}
		r.config = nil
		r.nodeRendererFuncsTmp = nil
	})
	writer, ok := w.(util.BufWriter)
	if !ok {
		writer = bufio.NewWriter(w)
	}
	err := ast.Walk(n, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
		s := ast.WalkStatus(ast.WalkContinue)
		var err error
		f := r.nodeRendererFuncs[n.Kind()]
		if f != nil {
			s, err = f(writer, source, n, entering)
		}
		return s, err
	})
	if err != nil {
		return err
	}
	return writer.Flush()
}