Some applications can be particularly sensitive to cold start, which is the amount of time it takes for an application to be initialized and start processing work. The Azure Functions team is constantly making improvements to cold start, and today, we’re pleased to announce a preview of major improvements for .NET apps using the isolated worker model.
The main change is a platform feature that you can enable through the addition of an application setting and some changes to your project file. This will allow the platform to start your app much more quickly than before.
For more info: https://learn.microsoft.com/azure/azure-functions/dotnet-isolated-process-guide#performance-optimizations