An example on how to use channels

Channels.cs

using System.Threading;
using System.Threading.Channels;
using System.Threading.Tasks;

class Processor<T> where T : class
{
    private readonly Channel<T> _channel = Channel.CreateUnbounded<T>();
    private readonly Task processors;

    public Processor(Func<T, Task> action, int numberOfConsumers = 4)
        => this.processors = Task.WhenAll(Enumerable.Range(0, numberOfConsumers).Select(_ => CreateProcessor(action)));
    public ValueTask Add(T job) => _channel.Writer.WriteAsync(job);

    public Task Complete() {
        _channel.Writer.Complete();
        return processors;
    }

    private async Task CreateProcessor(Func<T, Task> action) {
        while (await _channel.Reader.WaitToReadAsync()) {
            var job = await _channel.Reader.ReadAsync();
            try {
                    await action(job);
            }
            catch {
                    // handle exceptions
            }
        }
    }
}

var p = new Processor<string>(async id => {
    Console.WriteLine($"Started #{id}");
    await Task.Delay(5000);
    Console.WriteLine($"Finished #{id}");
});

while (Console.ReadLine() is string input && input != "x") await p.Add(input);

await p.Complete();