public static Task UploadHeadImg(string kf_account, string filename, Stream fileStream, ApiConfig config = null) { return(ApiHelper.UploadVoid("https://api.weixin.qq.com/customservice/kfaccount/uploadheadimg?$acac$&kf_account=" + Uri.EscapeDataString(kf_account), "media", filename, fileStream, null, config)); }