using System;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        //Run();

        FromResult();

    }

    public static void Run()

    {

        try 

        {

            var stringTask = GetStringAsyncRun(null);

            try

            {

                Task.WaitAll(stringTask);

            }

            catch (Exception)

            {

                Console.WriteLine("Inner");

            }

        }

        catch (Exception)

        {

            Console.WriteLine("Outer");

        }

    }

    public static void FromResult()

    {

        try 

        {

            var stringTask = GetStringAsyncFromResult(null);

            try

            {

                Task.WaitAll(stringTask);

            }

            catch (Exception)

            {

                Console.WriteLine("Inner");

            }

        }

        catch (Exception)

        {

            Console.WriteLine("Outer");

        }

    }

    public static Task<string> GetStringAsyncRun(string a)

    {

        return Task.Run(() => {

            if (a == null) {

                throw new Exception();

            }

​

            return a;

        });

    }

    public static Task<string> GetStringAsyncFromResult(string a)

    {

        if (a == null) {

            throw new Exception();

        }

​

        return Task.FromResult(a);

    }

}