code: @VisibleForTesting
      void correlateTaskToWorkflowInDS(String taskId, String workflowInstanceId) {
          String workflowToTaskKey = nsKey(WORKFLOW_TO_TASKS, workflowInstanceId);
          dynoClient.sadd(workflowToTaskKey, taskId);
          logger.debug("Task mapped in WORKFLOW_TO_TASKS with workflowToTaskKey: {}, workflowId: {}, taskId: {}",
                  workflowToTaskKey, workflowInstanceId, taskId);
      }
docs: Stores the correlation of a task to the workflow instance in the datastore
  
  @param taskId the taskId to be correlated
  @param workflowInstanceId the workflowId to which the tasks belongs to