What’s new in .NET Core 3.x and .NET 5 for performance?

The newest version of the runtime, as well as the C# language itself, brings some very interesting features that are helping in writing high performance, memory-aware code. Some of those features are working out of the box, without a need to configure anything. Some must be used explicitly. Nevertheless, all they support the ongoing process of making .NET ecosystem faster and faster. Let's see what exactly those changes bring and how they can help us. For everyone's benefit!