[tryfinally]

The modern .NET runtime can get devirtualize interface calls and eliminate temporary object allocations in some scenarios. It's a bit of a black box - who knows when it actually works? - but still, it's a nice boost here and there.

[drzaiusx11]

I assume it's not a black box anymore, but maybe that's a non-free lang extension? I had assumed linq was part of .net core these days, but I haven't gotten around to checking (10+ years since I've had a serious .net project)

[pjmlp]

LINQ has always been around since it was introduced, the only non-free language extension in .NET were contracts that required VS Enterprise license.