Error lens is an amazing extension in Visual Code that shows you all the errors and warnings in realtime when you working on a file or you open a new project.
After installing Error lens, you only need to open or edit a file to see the effect and the validations of this extension in real-time.
The following is a list of common errors and warning in C# detected by Error lens
Error lens also has a configuration settings section. You can set a delay to show the errors and change the colors for each type of error.
The official repository in git:
Try it out!!