using System;

using System.Collections.Concurrent;

using System.Threading.Tasks;

using Serilog;

using Serilog.Sinks.SystemConsole;

​

class Program

{

    static readonly ILogger logger = new LoggerConfiguration()

        .MinimumLevel.Debug()

        .WriteTo.Async(a => a.Console(theme: AnsiConsoleTheme.Code))

        .CreateLogger();

​

    static async Task Main(string[] args)

    {

        // Set the number of concurrent requests

        int numberOfRequests = 100;

​

        // Create a thread-safe collection to store the results

        var results = new ConcurrentBag<string>();

​

        // Use ParallelOptions to limit the degree of parallelism

        var parallelOptions = new ParallelOptions { MaxDegreeOfParallelism = Environment.ProcessorCount };

​

        // Create and start the tasks

        await Parallel.ForEachAsync(Enumerable.Range(0, numberOfRequests), parallelOptions, async (i, token) =>

        {

            try

            {

                // Simulate some work

                await Task.Delay(100, token);

​

                // Add the result to the thread-safe collection

                results.Add($"Request {i} completed");

                logger.Information($"Request {i} completed");

            }

            catch (OperationCanceledException ex)

            {

                // Handle cancellation

                results.Add($"Request {i} cancelled");

                logger.Warning(ex, $"Request {i} cancelled");

            }

            catch (Exception ex) when (IsTransientException(ex))

            {

                // Handle transient exceptions

                results.Add($"Request {i} failed with transient error: {ex.Message}");

                logger.Warning(ex, $"Request {i} failed with transient error");

            }

            catch (Exception ex)

            {

                // Handle critical exceptions

                results.Add($"Request {i} failed with critical error: {ex.Message}");

                logger.Error(ex, $"Request {i} failed with critical error");

            }

        });

​

        // Print the results

        foreach (var result in results)

        {

            Console.WriteLine(result);

        }

​

        // Ensure all log messages are flushed to the sink before exiting

        Log.CloseAndFlush();

    }

​

    static bool IsTransientException(Exception ex)

    {

        // Define the types of exceptions that are considered transient

        return ex is TimeoutException ||

               ex is TaskCanceledException;

    }

}