using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading;

using System.Threading.Tasks;

using System.Runtime.CompilerServices;

​

public static class Program

{

    public static async Task Main()

    {

        using CancellationTokenSource cts = new();

        IAsyncEnumerable<int> sequence = Enumerable.Range(1, 10).ToAsyncEnumerable();

        IAsyncEnumerator<int> enumerator = sequence.GetAsyncEnumerator(cts.Token);

        cts.Cancel();

        bool moved = await enumerator.MoveNextAsync();

        Console.WriteLine($"moved: {moved}");

    }

​

#pragma warning disable 1998

    public static async IAsyncEnumerable<T> ToAsyncEnumerable2<T>(

#pragma warning restore 1998

        this IEnumerable<T> source,

        [EnumeratorCancellation] CancellationToken cancellationToken = default)

    {

        ArgumentNullException.ThrowIfNull(source);

        cancellationToken.ThrowIfCancellationRequested();

        using IEnumerator<T> enumerator = source.GetEnumerator();

        while (true)

        {

            cancellationToken.ThrowIfCancellationRequested();

            if (!enumerator.MoveNext()) break;

            yield return enumerator.Current;

        }

    }

}

​