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: extractor.go
    path of file: ./repos/stack-rpc-tutorials/micro-istio/plugins/server/istio_http
    
    the code of the file until where you have to start completion: package http

import (
	"fmt"
	"reflect"
	"strings"

	"github.com/micro/go-micro/registry"
)

func extractValue(v reflect.Type, d int) *registry.Value {
	if d == 3 {
    
func extractValue(v reflect.Type, d int) *registry.Value {
	if d == 3 {
		return nil
	}
	if v == nil {
		return nil
	}

	if v.Kind() == reflect.Ptr {
		v = v.Elem()
	}

	arg := &registry.Value{
		Name: v.Name(),
		Type: v.Name(),
	}

	switch v.Kind() {
	case reflect.Struct:
		for i := 0; i < v.NumField(); i++ {
			f := v.Field(i)
			val := extractValue(f.Type, d+1)
			if val == nil {
				continue
			}

			// if we can find a json tag use it
			if tags := f.Tag.Get("json"); len(tags) > 0 {
				parts := strings.Split(tags, ",")
				val.Name = parts[0]
			}

			// if there's no name default it
			if len(val.Name) == 0 {
				val.Name = v.Field(i).Name
			}

			arg.Values = append(arg.Values, val)
		}
	case reflect.Slice:
		p := v.Elem()
		if p.Kind() == reflect.Ptr {
			p = p.Elem()
		}
		arg.Type = "[]" + p.Name()
		val := extractValue(v.Elem(), d+1)
		if val != nil {
			arg.Values = append(arg.Values, val)
		}
	}

	return arg
}