I am very new to Camunda. I am trying to achieve a scenario where one service task will call a external REST API to validate some data (it might take few hours to validate in the external system) and it should be async and once the next process (may be a receive task) gets some kind of callback it will continue. Please suggest what will be the best approach to achieve this.
Please find below the image for reference. I have created one more box at top just to simulate external system.