docs: public Task startTask(String taskId) {
      Task currentTask = associationManager.getTask();
      if(currentTask != null && currentTask.getId().equals(taskId)) {
        return currentTask;
      }
      Task task = processEngine.getTaskService().createTaskQuery().taskId(taskId).singleResult();
      if(task == null) {
        throw new ProcessEngineCdiException("Cannot resume task with id '"+taskId+"', no such task.");
      }
      associationManager.setTask(task);
      associateExecutionById(task.getExecutionId());
      return task;
    }