.NET Fiddle

CSharp · Console

/Program.cs

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Channels;
using System.Threading.Tasks;

public class Program
{
    public static void Main()
    {
        List<Channel<int>> channels = new();

        async Task CreateConsumer(Func<Channel<int>, Task> body)
        {
            var channel = Channel.CreateUnbounded<int>();
            lock (channels) channels.Add(channel);
            try
            {
                await Task.Run(() => body(channel)).ConfigureAwait(false);
            }
            finally
            {
                lock (channels) channels.Remove(channel);
            }
        }

        Task consumer1 = CreateConsumer(async channel =>
        {
            await foreach (var i in channel.Reader.ReadAllAsync())
            {
                Console.WriteLine($"Consumer one: {i}");
            }
        });

        Task consumer2 = CreateConsumer(async channel =>
        {
            await foreach (var i in channel.Reader.ReadAllAsync())
            {
                Console.WriteLine($"Consumer two: {i}");
            }
        });

        using CancellationTokenSource cts = new(TimeSpan.FromMilliseconds(3000));
        Task producer = Task.Run(async () =>
        {
            int i = 0;
            while (true)
            {
                i++;
                lock (channels) channels.ForEach(channel => channel.Writer.TryWrite(i));
                try { await Task.Delay(TimeSpan.FromMilliseconds(250), cts.Token); }
                catch (OperationCanceledException) { break; }
            }
        });

        producer.Wait();
        lock (channels) channels.ForEach(channel => channel.Writer.Complete());
        Task.WaitAll(consumer1, consumer2);
    }
}