LinqToTask.cs

static class LinQToTaskExtensions
    {
        public static Func<Task<TResult>> Select<TSource, TResult>(
            this Task<TSource> source, Func<TSource, TResult> selector)
        {
            return async () =>
            {
                var sourceResult = await source;
                if (sourceResult == null)
                    return default(TResult);
                return selector(sourceResult);
            };
        }

        public static Func<Task<TResult>> SelectMany<TSource, TResult>(this Func<Task<TSource>> source,
            Func<TSource, Task<TResult>> selector)
        {
            return async () =>
            {
                var sourceResult = await source();
                if (sourceResult == null)
                    return default(TResult);
                return await selector.Invoke(sourceResult);
            };

        }

    public static Func<Task<TSource>> Aggregate<TSource>(this IEnumerable<Task<TSource>> source,
            Func<Func<Task<TSource>>, Func<Task<TSource>>, Func<Task<TSource>>> func)
        {
            return async () =>
            {
                return await source.Aggregate((task, task1) =>
                    func.Invoke(() => task, () => task1)());
            };
        }
        public static Func<Task<TSource>> AggregateWhile<TSource>(this IEnumerable<Task<TSource>> source,
            Func<Func<Task<TSource>>, Func<Task<TSource>>, Func<Task<TSource>>> func, Func<TSource, bool> predicate)
        {
            return async () =>
            {
                Func<Task<TSource>> total = () => Task.FromResult(default(TSource));
                foreach (var task in source)
                {
                    var result = func.Invoke(total, () => task);
                    if (!predicate(await result()))
                        break;
                    total = result;
                }

                return await total.Invoke();
            };
        }
    }