C# Anatomy of Async and Await - Part 2

This is second part of C# Anatomy of Async and Await series, feel free to go through all parts listed following :

• https://www.usmanrafiq.com/2020/07/anatomy-of-async-and-await-part-1.html Part 1

• https://www.usmanrafiq.com/2020/07/c-anatomy-of-async-and-await-part-2.html Part 2

Today we are going to see some of the best practices to get maximum out of Asyn & Await in C#. First it is not recommended at all to call asynchronous methods synchronously but lets say in some situation we have to some how, then we should make sure that we are not calling  

Synchronization context is another key factor which we usually ignore, it means that to return execution control to the same thread which started that asynchronous task, it is important when the stater thread is UI but it make no sense if it was not main / UI thread, in that case the cost of context switching will be apply and overall performance of the application will hurt.

So the rule is if its a web app / api apply ConfigureAwait(false) for every asynchronous call, only avoid it if we want to return execution control to starter thread ( UI tread , caller ).

Most of the time a code base is structured in layered form, where we have separate modules in separate projects and all those library projects are referenced from within the main or executing project. You will agree with me that in most of the cases one library method get called from within another and this chain keep growing till last library get called from the executing project where the actual results are required. So the reason to create that scenario is that when this happen make sure you return Task from the methods if the output is not required for further processing. In short if we have method which can return task, don't make it async, in this way code will run little more fast as we will not be doing context switching.

Next is never wrap method call returning a task into try catch block, because that piece of code will run synchronously and if any exception get occurred in that task will not be pop up because the execution control is not waiting for that task to get completed.

Those were some of the most important points I wanted to share in this blog post, hope that will help you to improve your code and its performance and yes there is a lot more to come ;)