Can you explain the main principles and features of ASP.NET Core?

ASP.NET Core is a cross-platform, high-performance framework for building modern web applications and APIs. Its main principles and features include:

• Cross-platform support: runs on Windows, Linux, and macOS.
• Modular architecture: uses lightweight components that can be included as needed.
• Built-in Dependency Injection (DI): simplifies dependency management.
• Middleware pipeline: allows flexible configuration of HTTP request processing.
• Support for Razor Pages and MVC: for creating web interfaces.
• High performance: optimized for fast response times.
• Open Source: code is available on GitHub, promoting transparency and community development.

Example of simple middleware in ASP.NET Core:

app.Use(async (context, next) => {
    Console.WriteLine("Before next middleware");
    await next();
    Console.WriteLine("After next middleware");
});