TaskAsyncEnumerable.cs

public class TaskAsyncEnumerable<T> : IAsyncEnumerable<T>
    {
        private Func<Task<Option<T>>> _asyncTask;
        private TimeSpan timeSpan;

        public TaskAsyncEnumerable(Func<Task<Option<T>>> asyncTask)
        {
            _asyncTask = asyncTask;
        }

        public TaskAsyncEnumerable(Func<Task<Option<T>>> taskOption, TimeSpan timeSpan)
        {
            this._asyncTask = taskOption;
            this.timeSpan = timeSpan;
        }

        public IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken = new CancellationToken())
        {
            return new TaskAsyncEnumerator<T>(_asyncTask,timeSpan,cancellationToken);
        }
    }
    public class TaskAsyncEnumerator<T> : IAsyncEnumerator<T>
    {
        private Func<Task<Option<T>>> _asyncTask;
        private readonly CancellationToken _cancellationToken;
        private TimeSpan _timeSpan;

        public TaskAsyncEnumerator(Func<Task<Option<T>>> asyncTask, CancellationToken cancellationToken)
        {
            _asyncTask = asyncTask;
            _cancellationToken = cancellationToken;
        }

        public TaskAsyncEnumerator(Func<Task<Option<T>>> asyncTask,TimeSpan timeSpan, CancellationToken cancellationToken)
        {
            _timeSpan = timeSpan;
            _asyncTask = asyncTask;
            _cancellationToken = cancellationToken;
        }

        public  ValueTask DisposeAsync()
        {
            return new ValueTask(Task.CompletedTask);
        }

        public async ValueTask<bool> MoveNextAsync()
        {
            if (_timeSpan != TimeSpan.Zero)
                await Task.Delay(_timeSpan,_cancellationToken);

            var result=await _asyncTask.Invoke();
            result.MatchSome(obj =>Current= obj);
            return result.HasValue;
        }

        public T Current { get; private set; }
    }