code: @Override
    protected void initializeVariableInstanceBackPointer(VariableInstanceEntity variableInstance) {
      if (processInstanceId != null) {
        variableInstance.setProcessInstanceId(processInstanceId);
      } else {
        variableInstance.setProcessInstanceId(id);
      }
      variableInstance.setExecutionId(id);
    }
docs: TODO: this should ideally move to another place