code: public static function beginTransaction($connection)
      {
          $connection->query = 'BEGIN_TRANSACTION';
          $connection->method = 'POST';
          $connection->action = '/_query';
          return self::sendQuery($connection);
      }
docs: Set query parametrs to execute - Begin Transaction.
  
  @param  \stdClass $connection
  @return \Clusterpoint\Response\Single