.NET has the ability to handle your memory layout explicitly with structs.

They expanded on that functionality with span and made sure that the common libraries is implemented using this.

If you do textbook OOP development for everything, you will end up with a lot of allocations and what not, which was the case, so they went through the entire base class library and rewrote all often used methods to be faster.

they even posted a bunch of posts with all their improvement tricks: https://devblogs.microsoft.com/dotnet/performance-improvemen...