docs: public static <T> T callInTransaction(String tableName, final ConnectionSource connectionSource,
  			final Callable<T> callable) throws SQLException {
  
  		DatabaseConnection connection = connectionSource.getReadWriteConnection(tableName);
  		try {
  			boolean saved = connectionSource.saveSpecialConnection(connection);
  			return callInTransaction(connection, saved, connectionSource.getDatabaseType(), callable);
  		} finally {
  			// we should clear aggressively
  			connectionSource.clearSpecialConnection(connection);
  			connectionSource.releaseConnection(connection);
  		}
  	}