Async/Await Tutorial in C#

Async-Await-Tutorial.cs

    public class Program
    {
        public static void Main(string[] args)
        {
            DoSomethingAsync();
            Console.ReadLine();
        }

        public static async void DoSomethingAsync()
        {
            Console.WriteLine("Entering the main calling function");

            var task = ExpensiveOperation(); 
            
            //When "ExpensiveOperation" awaits the task, the running thread will return to this point and continue execution.

            Console.WriteLine("Concurrent thread is now running in the background"); 

            await task; //At this point, the running thread will return to the thread pool.

            Console.WriteLine("Operation completed"); //This will execute after the task is completed
        }

        public static async Task<bool> ExpensiveOperation()
        {
            Console.WriteLine("Entering sub-function");

            /* 
             * Using the await keyword, you indicate that any operation following the awaited task is a continuation to the 
             * task.
             * 
             * At this point, the current thread will return to the calling method (and in case the calling method is awaiting
             * this task, then the current thread will return to the thread pool) until the awaited task is completed / returns, 
             * then a background thread will be assigned to serve the continuation
             */

            var response = await Task.Run(() =>
            {
                Thread.Sleep(5000);
                Console.WriteLine("Concurrent thread will return now");
                return true;
            });

            //The below is a continuation to the above task that will run when the task returns
            Console.WriteLine("Task completed");
            return response;
        }
    }