using System;
using System.Threading.Tasks;

public class Ex4
{
    public static async Task Run()
    {
        /* Example working with Tasks and awaiting them later */
        var lowerCaseString = "i want to be an upper case string";
        Console.WriteLine("main: " + lowerCaseString);
        // Start the task but do not await yet
        Task<string> upperCaseTask = WorkOnStringAsync(lowerCaseString);
        Console.WriteLine("main: WorkOnStringAsync has been called, doing other work...");
        // Now await the result
        Console.WriteLine("main: Now waiting for the result");
        var upperCaseString = await upperCaseTask;
        Console.WriteLine("main: " + upperCaseString);
    }

    private static async Task<string> WorkOnStringAsync(string s)
    {
        Console.WriteLine("Task: Async task started");
        Console.WriteLine("Task: Waiting for 2 sec");
        await Task.Delay(2000);
        Console.WriteLine("Task: Done waiting, returning the upper case string");
        return s.ToUpper();
    }
}