How to implement guide with unhandled task handling in c# when using parallel.foreach with async calls
I'm working with an scenario when trying to perform asynchronous operations within a `Parallel.ForEach` loop in C#. When I try to run multiple asynchronous tasks in parallel, I often get the behavior: `System.AggregateException: One or more errors occurred. ---> System.InvalidOperationException: The operation want to be completed because the 'await' command want to be used in this context.` Here’s a snippet of my code that illustrates the scenario: ```csharp public async Task ProcessItemsAsync(IEnumerable<Item> items) { Parallel.ForEach(items, async item => { await ProcessItemAsync(item); }); } private async Task ProcessItemAsync(Item item) { // Simulate some asynchronous work await Task.Delay(1000); Console.WriteLine($"Processed item: {item.Id}"); } ``` I've tried changing the `Parallel.ForEach` to a normal `foreach` loop and it works perfectly. However, the performance with `foreach` isn't as good as I would like due to the sequential execution. I want to maintain the parallelism while still being able to wait for the tasks to complete. Another approach I tried was to collect the tasks into a list and then await them all at once: ```csharp public async Task ProcessItemsAsync(IEnumerable<Item> items) { var tasks = new List<Task>(); foreach (var item in items) { tasks.Add(ProcessItemAsync(item)); } await Task.WhenAll(tasks); } ``` This works fine, but I’m wondering if there’s a way to achieve true parallelism while still using async/await. Is it possible to have both the benefits of `Parallel.ForEach` and async/await without running into this exception? Any insights or best practices would be greatly appreciated! I'm using .NET 6.0 and C# 10.0. For reference, this is a production microservice. Could someone point me to the right documentation?