Code Review!

ParallelRunner.cs

    public class ParallelRunner<T>
    {
        private List<Task<List<T>>> Tasks { get; } = new List<Task<List<T>>>();

        /// <summary>
        /// Queues the specified work to run
        /// </summary>
        public void Run(Task<List<T>> task)
        {
            Tasks.Add(task);
        }

        /// <summary>
        /// Wait for all enqueued work to finish and returns a list of <see cref="T:System.Threading.Tasks.Task`1" />
        /// </summary>
        public async Task<IEnumerable<T>> Result()
        {
            var result = await Task.WhenAll(Tasks);
            return result.SelectMany(o => o);
        }

        public void Run(Task<T> task)
        {
            Tasks.Add(task.ContinueWith(t => new List<T>{t.Result}));
        }
    }