ValueTask support

[mikasoukhov]

Here is some my own extensions (maybe will be interested to join with Nito's code, like you proj and use it):

public static async ValueTask AsValueTask<T>(this ValueTask<T> valueTask)
			=> await valueTask;

		public static ValueTask<T> AsValueTask<T>(this Task<T> task)
			=> new(task);

		public static ValueTask AsValueTask<T>(this Task task)
			=> new(task);

		public static async ValueTask<T[]> WhenAll<T>(this IEnumerable<ValueTask<T>> tasks)
		{
			if (tasks is null)
				throw new ArgumentNullException(nameof(tasks));

			List<Exception> exceptions = null;

			var source = tasks.ToArray();

			var results = new T[source.Length];

			for (var i = 0; i < source.Length; i++)
			{
				try
				{
					results[i] = await source[i].ConfigureAwait(false);
				}
				catch (Exception ex)
				{
					exceptions ??= new List<Exception>(source.Length);
					exceptions.Add(ex);
				}
			}

			if (exceptions is not null)
				throw new AggregateException(exceptions);

			return results;
		}

		public static async ValueTask WhenAll(this IEnumerable<ValueTask> tasks)
		{
			if (tasks is null)
				throw new ArgumentNullException(nameof(tasks));

			List<Exception> exceptions = null;

			var source = tasks.ToArray();

			for (var i = 0; i < source.Length; i++)
			{
				try
				{
					await source[i].ConfigureAwait(false);
				}
				catch (Exception ex)
				{
					exceptions ??= new List<Exception>(source.Length);
					exceptions.Add(ex);
				}
			}

			if (exceptions is not null)
				throw new AggregateException(exceptions);
		}

		public static void Run(Func<ValueTask> getTask)
		{
			if (getTask is null)
				throw new ArgumentNullException(nameof(getTask));

			AsyncContext.Run(() => getTask().AsTask());
		}

		public static T Run<T>(Func<ValueTask<T>> getTask)
		{
			if (getTask is null)
				throw new ArgumentNullException(nameof(getTask));

			return AsyncContext.Run(() => getTask().AsTask());
		}

[BalassaMarton]

It would be quite inconvenient to have this name for a static utility class now that there's void ValueTask.