Async example

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace TestAsync
{
    class Program
    {
        static async Task Main(string[] args)
        {
            await Example5Async();
            
            Console.WriteLine("End!");
            Console.ReadLine();
        }

        static async Task Example1Async()
        {
            var task1 = Task1();
            await task1;
            var task2 = Task2();
            await task2;
        }

        static async Task Example2Async()
        {
            var task1 = Task1();
            var task2 = Task2();
            await task1;
            await task2;
        }

        static void Example3Async()
        {
            Task1();
            Task2();
        }

        static async Task Example4Async()
        {
            var task1 = Task1();
            var task2 = Task2();
            var allTasks = new Task[] { task1, task2 };
            await Task.WhenAll(allTasks);
        }

        static async Task Example5Async()
        {
            var task1 = Task1();
            var task2 = Task2();
            var allTasks = new List<Task> { task1, task2 };
            while (allTasks.Any())
            {
                Task finished = await Task.WhenAny(allTasks);
                allTasks.Remove(finished);
            }
        }

        static async Task<string> Task1()
        {
            var task1 = Task.Run(async () => {
                await Task.Delay(5000);
                Console.WriteLine("Task 1");
                return "Hello";
            });
            return await task1;
        }

        static async Task<string> Task2()
        {
            var task2 = Task.Run(async () => {
                await Task.Delay(3000);
                Console.WriteLine("Task 2");
                return "Hello";
            });
            return await task2;
        }
    }
}