public static class Program
{
    public static void Main()
    {
        object x = await GetAsync(); // Make method async
    }

    private static Task<object> GetAsync() => Task.FromResult(default(object));
}

public static class Program
{
    public static async Task Main()
    {
        object x = await GetAsync();
    }
}

public static class Program
{
    public static async Task MainAsync()
    {
        object x = await GetAsync();
    }
}