using System;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        try {

            new Imp().MethodThrowsException("").GetAwaiter().GetResult();

        }catch(Exception ex)

        {

            Console.WriteLine(ex.Message);

        }

    }

​

}

​

public class Imp {

    public async void MethodThrowsException(string test){

        if(string.IsNullOrWhiteSpace(test))

            throw new NotImplementedException();

        await Task.CompletedTask;

    }

}

​