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: json.go
    path of file: ./repos/iris/middleware/accesslog
    
    the code of the file until where you have to start completion: package accesslog

import (
	"bytes"
	"io"
	"strconv"
	"strings"

	jsoniter "github.com/json-iterator/go"
)

// JSON is a Formatter type for JSON logs.
type JSON struct {
	// Indent in spaces.
	// Note that, if set to > 0 then jsoniter is used instead of easyjson.
	Indent     string
	EscapeHTML bool
	HumanTime  bool

	jsoniter jsoniter.API
	ac       *AccessLog
}

// SetOutput creates the json encoder writes to the "dest".
// It's called automatically by the middleware when this Formatter is used.
func (f *JSON) SetOutput(dest 
    
func (f *JSON) Format(log *Log) (bool, error) {
	if f.jsoniter != nil {
		if f.HumanTime {
			// 1. Don't write the unix timestamp,
			// key will be visible though as we don't omit the field.
			log.Timestamp = 0
		}

		b, err := f.jsoniter.Marshal(log)
		if err != nil {
			return true, err
		}

		if f.HumanTime {
			// 2. Get the time text based on the configuration.
			t := log.Now.Format(log.TimeFormat)

			// 3. Find the "timestamp:$indent"
			// and set it to the text one.
			var (
				oldT  []byte
				tsKey []byte
			)

			if f.Indent != "" {
				oldT = timestampIndentKeyVB
				tsKey = timestampKeyIndentB
			} else {
				oldT = timestampKeyVB
				tsKey = timestampKeyB
			}

			newT := append(tsKey, strconv.Quote(t)...)
			b = bytes.Replace(b, oldT, newT, 1)
		}

		f.ac.Write(append(b, newLine))
		return true, nil
	}

	err := f.writeEasyJSON(log)
	return true, err
}