/// <summary>
 /// sync/async prepare
 /// </summary>
 /// <param name="nextAction"></param>
 internal void InternalPrepare(Action nextAction = null)
 {
     //prepare sql command;
     _isPreparedStmt = true;
     _query = new Query(Connection.Conn, _sqlStringTemplate, Parameters);
     _query.Prepare(nextAction);
 }