async Task<object> Scalar(string sql)
        {
            if (!inited)
                await Init();

            object o = null;
            //are.WaitOne();
            sqlcmd.CommandText = sql;
            if (sqlconn.State == ConnectionState.Open)
            {
                var hold = true;
            }
            await sqlconn.OpenAsync();
            await sqlcmd.ExecuteScalarAsync();
            sqlconn.Close();
            
            //are.Set();
            return o;
        }

url_lst.ForEach(async (item) =>
                        {
                            var uri = new Uri(item);
                            if (!await q_ing.Contains(uri) && !await q_ed.Contains(uri))
                                await q_ing.En(uri);
                        });