async/await

async_await.cs

class Program
{
    public static void Main()
    {
        Console.WriteLine("-- Main is on: " + Thread.CurrentThread.ManagedThreadId);
        Console.WriteLine("Hey David, How much is 98745 divided by 7?");

        Task<int> david = ThinkAboutIt();

        Console.WriteLine("While he thinks, lets chat about the weather for a bit.");
        Console.WriteLine("Do you think it's going to rain tomorrow?");
        Console.WriteLine("No, I think it should be sunny.");

        Console.WriteLine("-- Main is still on: " + Thread.CurrentThread.ManagedThreadId);

        var davidsAnswer = david.Result;

        Console.WriteLine("-- Main is still on: " + Thread.CurrentThread.ManagedThreadId);

        Console.WriteLine($"David: {davidsAnswer}");
    }

    private static async Task<int> ThinkAboutIt()
    {
        Console.WriteLine("-- Starting thinking on: " + Thread.CurrentThread.ManagedThreadId);
        await ReadTheManual();
        
        Console.WriteLine("-- Thinking on: " + Thread.CurrentThread.ManagedThreadId);
        return (98745 / 7);
    }

    private static async Task ReadTheManual()
    {
        Console.WriteLine("-- Starting reading a manual on: " + Thread.CurrentThread.ManagedThreadId);
        await Task.Delay(TimeSpan.FromSeconds(1));
        
        Console.WriteLine("-- Done reading manual on: " + Thread.CurrentThread.ManagedThreadId);
    }
}