Implementing an Asynchronous Controller Action Method

Steps to implement an asynchronous controller action method

Now, we are going to change the implementation of the unanswered questions endpoint so that it's asynchronous:

1. We are going to start by creating an asynchronous version of the data repository method that gets unanswered questions. So, let's create a new method in the data repository interface underneath GetUnansweredQuestions in IDataRepository.cs: