jsonUnmarshal fail from a jsonMarshal result of *network.Cookie

[bronze1man]

follow code will panic:

package main

import (
   	"github.com/chromedp/cdproto/network"
	"encoding/json"
)
func main() {
	b,err:=json.Marshal(&network.Cookie{})
	if err!=nil{
		panic(err)
	}
	var c *network.Cookie
	err=json.Unmarshal(b,&c)
	if err!=nil{
		panic(err)
	}
	return
}