In the previous chapter (Chapter 7, Implementing Design Patterns for Web Applications - Part 2), we created a sample web application with the help of various patterns for the web. We adapted authorization and authentication mechanisms to secure a web application and discussed Test-driven development (TDD) to make sure that our code has been tested and is working.

This chapter will discuss the best practices to adopt while performing concurrent programming in .NET Core. In the upcoming sections of this chapter, we will learn about the design patterns relevant for well-organized concurrency in C# and .NET Core applications.

The following topics will be covered in this chapter:

• Async/Await – Why is blocking bad?
• Multithreading and asynchronous programming
• Concurrent collections
• Patterns and practices – TDD and Parallel LINQ