DMA (Direct Memory access)

DMA code has known in .NET world as unsafe code and there you can even use pointers too for memory access. Here you will get a start https://www.c-sharpcorner.com/article/pointers-in-C-Sharp/

 

But if you write unsafe programming, then don't use C#, use C, C++ etc... Because you are not getting benefits of .NET framework like GB Collector. This is my perspective as each programming model and language has it's own purpose. Writing a model inside another different model not making sense, expect with a very strong reason.