using System;

using System.Threading.Tasks;

​

namespace AsyncWarning

{

  public class Program

    {

        static async Task Main()

        {

            Console.WriteLine("Entering Main() application entry point.");

​

            int millisecondsDelay = 2000;

            await CallingMethodAsync(millisecondsDelay);

​

            Console.WriteLine("Exiting Main() application entry point.");

​

            await Task.Delay(millisecondsDelay + 500);

        }

​

        static async Task CallingMethodAsync(int millisecondsDelay)

        {

            Console.WriteLine("  Entering calling method.");

​

            // Call #1.

            // Call an async method. Because you don't await it, its completion

            // isn't coordinated with the current method, CallingMethodAsync.

            // The following line causes warning CS4014.

            // CalledMethodAsync(millisecondsDelay);

​

            // Call #2.

            // To suppress the warning without awaiting, you can assign the

            // returned task to a variable. The assignment doesn't change how

            // the program runs. However, recommended practice is always to

            // await a call to an async method.

​

            // Replace Call #1 with the following line.

            //Task delayTask = CalledMethodAsync(millisecondsDelay);

​

            // Call #3

            // To contrast with an awaited call, replace the unawaited call

            // (Call #1 or Call #2) with the following awaited call. Best

            // practice is to await the call.

​

            // await CalledMethodAsync(millisecondsDelay);

​

            Console.WriteLine("  Returning from calling method.");

        }

​

        static async Task CalledMethodAsync(int millisecondsDelay)

        {

            Console.WriteLine("    Entering called method, starting and awaiting Task.Delay.");

​

            await Task.Delay(millisecondsDelay);

​

            Console.WriteLine("    Task.Delay is finished--returning from called method.");

        }

    }

​

    // Output with Call #1 or Call #2. (Wait for the last line to appear.)

​

    // Entering Main() application entry point.

    //   Entering calling method.

    //     Entering called method, starting and awaiting Task.Delay.

    //   Returning from calling method.

    // Exiting Main() application entry point.

    //     Task.Delay is finished--returning from called method.

​

    // Output with Call #3, which awaits the call to CalledMethodAsync.

​

    // Entering Main() application entry point.

    //   Entering calling method.

    //     Entering called method, starting and awaiting Task.Delay.

    //     Task.Delay is finished--returning from called method.

    //   Returning from calling method.

    // Exiting Main() application entry point.

}