Task operations

Scenario:

Setup users async way.

Solution:

Create multiple tasks to setup users and based on response add the details to collection and return. Also handle exceptions.

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using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class ProgramTaskErrorHandling
    {
        static void Main(string[] args)
        {
            var users = new List<User>() { };
            var items = SetupUsers(users);
        }

        private static async Task<List<User>> SetupUsers(List<User> users)
        {
            var tasks = new List<Task<List<User>>>();

            foreach (var user in users)
            {
                tasks.Add(Setup(user));
            }

            //ConcurrentBag allows generic data to be stored in unordered from and is a thread-safe allowing multiple threads to use it. 
            var result = new ConcurrentBag<User>();

            while (tasks.Count > 0)
            {
                var task = await Task.WhenAny(tasks).ConfigureAwait(false);

                if (task.IsFaulted)
                {
                    throw task.Exception == null ? new System.Exception("Task without exception") : task.Exception.Flatten().InnerExceptions[0];
                }

                if (!task.IsFaulted)
                {
                    foreach (var item in task.Result)
                    {
                        result.Add(item);
                    }
                }

                tasks.Remove(task);
            }

            return result.ToList();
        }

        private static Task<List<User>> Setup(User user)
        {
            throw new System.NotImplementedException();
        }
    }

    internal class User
    {
    }
}