Optimizing Asynchronous Programming in .NET: Key Takeaways from MTG Toulouse’s Tech Session

Diving into Best Practices for async/await in .NET

On April 2, 2025, I attended a tech session organized by MTG Toulouse, featuring Sébastien Pertus , Senior Software Engineer at Microsoft. While I was already familiar with async/await and had used it in my projects, this session provided a deeper understanding of its mechanics and introduced me to best practices that can significantly improve performance and maintainability.

Overview

Sébastien started with a brief history of async/await and how asynchronous programming was previously implepented. He then explained its key concepts, best practices, and common pitfalls. The session included real code demos and interactive Q&A, making the concepts clear and practical.

Key Best Practices and Insights

One of the biggest takeaways from this session was the importance of mastering the nuances of async/await. Here are some of the most valuable insights:

• Avoid async void: While commonly used in event handlers, async void makes exception handling difficult. Instead, using async Task ensures that exceptions can be properly awaited and handled.
• Be cautious with .Result or .Wait(): These blocking calls can lead to deadlocks and performance issues. Instead, using .GetAwaiter().GetResult() is a safer alternative when synchronous execution is required.
• Understanding ConfigureAwait(false): This can optimize performance by preventing the thread from returning to the original synchronization context. However, it should be used carefully, especially in UI-based applications like WPF or ASP.NET, where it may cause unexpected behavior.
• ValueTask vs Task: ValueTask can improve efficiency by reducing memory allocations, but it should not be used indiscriminately. In scenarios where a task is awaited multiple times, Task remains the better choice.
• IAsyncDisposable and IAsyncEnumerable: These features improve resource management and handling asynchronous collections, making them valuable for scenarios involving large-scale data processing.

What I Learned

Even though I have already worked with async/await, this session refined my understanding of its complexity. Concepts like better exception handling, optimizing performance with ConfigureAwait(false), and choosing between Task and ValueTask were particularly insightful.

I also appreciated the references to industry experts like Stephen Toub and David Fowler, whose recommendations on handling tasks and exceptions provided valuable context for real-world development.

What Could Have Been Better

Certain advanced concepts were covered quickly, and a longer session might have allowed for deeper exploration of specific use cases.

Conclusion

This session on async/await in .NET was a great opportunity to refine my skills and integrate best practices into my future projects. For any developer working with .NET, mastering these techniques is essential to writing efficient and reliable asynchronous code.

A big thanks to Thomas Bolon for organizing the event and to Benoît Laut for the other part of the conference!

📌 Useful Resources:

🔗 Microsoft’s official async/await documentation

🔗 Stephen Toub’s talk on async/await

https://youtu.be/R-z2Hv-7nxk?si=iJbu63jaYQT3CIiq

🔗David Fowler

https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/blob/master/AsyncGuidance.md

💬 How do you optimize async/await in your .NET projects?

#dotnet #asynchronous #asyncawait #Microsoft #MTGToulouse MTG:Toulouse Microsoft