cocos2dx-lua 如何加载网络图片？？？

Cocos2d-x
#1

使用的是3.14.1版本

#2 
local xhr = cc.XMLHttpRequest:new()
xhr.responseType = cc.XMLHTTPREQUEST_RESPONSE_ARRAY_BUFFER
xhr:open("GET", url)
xhr.tag = tag

local function onCallBack()
	
    if xhr.readyState == 4 and (xhr.status >= 200 and xhr.status < 207) then
        local response   = xhr.response
        local size = table.getn(response)
        local  file = io.open(path,"w")
        for i=1,size do 
        	 file:write(string.char(response[i]))
        end
        file:flush()
        file:close()
        self:createImg(path)
    else
        print("xhr.readyState is:" .. xhr.readyState .. "  xhr.status is: " .. xhr.status)
        G_GlobalFunc:showAlertLayer(self._widget,"获取失败")
    end
	xhr:unregisterScriptHandler()
end
xhr:registerScriptHandler(onCallBack)
xhr:send()