docs: public static Connection getConnection() throws SQLException {
          if (LOGGER.isTraceEnabled()) {
              Callstacks.printCallstack(Level.TRACE, new String[]{"org.b3log"}, null);
          }
  
          if (Latkes.RuntimeDatabase.NONE == Latkes.getRuntimeDatabase()) {
              return null;
          }
  
          final Connection ret = hikari.getConnection();
          ret.setTransactionIsolation(transactionIsolationInt);
          ret.setAutoCommit(false);
  
          return ret;
      }