await is probably one of the most important features of C#. It has made the life of developers easy. It helps developers to write clean code without any callbacks which are messy and difficult to understand.However, if used incorrectly
await it can cause havoc. It can lead to performance issues, deadlocks which are hard to debug. I have burnt hands due to incorrect use of
async await in the past and based on my little experience I can tell these issues will make your life hell, you will start questioning your very existence on this earth or why you chose to be a developer 🙂
I have tried to add common pitfalls while using async
await below. These are some of my learnings while working on problems that arise due to incorrect use of async
await Much of these is inspired from Stephen Cleary blogs and Lucian Wischik six essential tips for Async channel 9 videos.
Here are tips:
- AVOID using
Task.Wait(). They make the calls synchronous and block async code.
- Make your calls
asyncall the way.
- USE `Task.Delay` instead of `Thread.Sleep`
- Understand the difference between CPU bound and IO bound operation before using Task Parallel Library or TPL
Parallel.ForEachfor CPU bound operation.
awaitfor IO bound operation.
ConfigureAwait(false)on the web APIs or library code. On the WPF application do not use
ConfigureAwait(false)at the top level methods.
- AVOID using `Task.Factory.StartNew`. Use
- DO NOT expose a synchronous method as asynchronous or visa vesra. In other words your library method should expose the true nature of method.
- DO NOT use
async voidother than top level Events. ALWAYS return
I hope these tips help few of you and help avoid common mistakes. Please suggest any other tips in the comments section.