Make all structs readonly when possible

[BobLd]

No description provided.

[EliotJones]

does this improve performance or is the benefit mainly code quality and compiler level checks? wonder if we could also start using records but I must admit I've missed a lot of C# changes recently so not sure what should be struct vs class vs record vs record struct

[EliotJones]

does this improve performance or is the benefit mainly code quality and compiler level checks? wonder if we could also start using records but I must admit I've missed a lot of C# changes recently so not sure what should be struct vs class vs record vs record struct

[BobLd]

@EliotJones it should improve performance slightly (related to defensive copy if I understand correctly, I would need to find back the article I found that was dicussing that), and it improves code quality for sure.

I agree on your point about record / record struct. I was planning to add a benchmark project at some point, this might be helpfull to assess what should be what