foo.cs

public async Task<int> mywebcontroller (int input) {
    if (input == 2) {
        return 4;
    } else {
        await Task.Delay(1000);
        return 3;
	}
}

async void Main()
{

	Console.WriteLine(await mywebcontroller(2));
	Console.WriteLine(await mywebcontroller(4));
}