using System;

using System.Threading.Tasks;

public class Program

{

    public static async Task Main()

    {

        await ExecuteActionAsync(Console.WriteLine, 42);

​

        var res = await ExecuteFuncAsync(_ => _, 42);

        Console.WriteLine(res);

    }

    static Task ExecuteActionAsync<TState>(

        Action<TState> callback, 

        TState state)

    {

        return Task.Factory.StartNew(static args => 

        {

            var local = (ValueTuple<TState, Action<TState>>)args;

            local.Item2(local.Item1);

        }, (state, callback));

    }

    static Task<TResult> ExecuteFuncAsync<TState, TResult>(

        Func<TState, TResult> callback,

        TState state)

    {

        return Task.Factory.StartNew<TResult>(static args => 

        {

            var local = (ValueTuple<TState, Func<TState, TResult>>)args;

            var (localCallback, localState) = (local.Item2, local.Item1);

            return localCallback(localState);

        }, (state, callback));

    }

}