AsyncWritter.cs

#nullable enable

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Channels;
using System.Threading.Tasks;
using System.Runtime.CompilerServices;
using BenchmarkDotNet.Attributes;

namespace MiniBench
{
    public class AsyncWriter
    {
        static readonly TestChannelWriter<int> channelWriter = new TestChannelWriter<int>(10000);

        private sealed class TestChannelWriter<T> : ChannelWriter<T>
        {
            private readonly int[] datapoints;
            private readonly int _max;
            private int _count;
            private int _index = 0;

            public TestChannelWriter(int max)
            {
                _max = max;
                Random _rand = new Random(42);
                datapoints = new int[max * 10];
                for (int i = 0; i < max * 10; i++)
                {
                    datapoints[i] = _rand.Next(0, 2);
                }
            } 

            public override bool TryWrite(T item)
            {
                // return true if we are under our limit, and add random failures
                return datapoints[_index++] == 0 && _count++ < _max;
            }

            public override ValueTask<bool> WaitToWriteAsync(CancellationToken cancellationToken)
            {
                if (_count >= _max)
                {
                    return new ValueTask<bool>(Task.FromResult(false));
                }
                else
                {
                    if (datapoints[_index++] == 0)
                    {
                        // introduce a delay
                        return new ValueTask<bool>(Task.Delay(1).ContinueWith(_ => true));
                        //int iter = 0;
                        //int limit = 1000_1000;
                        //while (iter++ < limit) ;
                    }
                    else
                    {
                        return new ValueTask<bool>(Task.FromResult(true));
                    }
                }
            }
        }

        [Benchmark]
        public async Task AsyncAwait()
        {
            int count = 0;
            try
            {
                while (true)
                {
                    await channelWriter.WriteAsync(count++);
                }
            }
            catch (ChannelClosedException)
            {
            }
        }
    }
}