Yup - this would do the job faster and better.
Task task = Task.Delay(TimeSpan.FromSeconds(1)); tasks.Add(task);
Task task = Task.Delay(TimeSpan.FromSeconds(1)); tasks.Add(task);
The difference is quite significant.
(1) With the authors code (using Task.Run), I get ~428MB of allocations.
(2) Dropping the unnecessary Task.Run(...), I get ~183MB of allocations.
(3) Doing (2) and waiting N times on the same delay, I get ~39MB of allocations.
This was all using .NET 6 too. .NET 7 or the 8 preview might be even better since they are working hard on performance in recent releases.
So even looking at just (2), that puts .NET on par with the rust library.