Prompt: Tái cấu trúc mã C# để đạt hiệu suất tối đa

Act as an expert in C#. Review the below-mentioned C# code and provide some suggestions about better performance. It does not matter if you have to write more code or less readable one, performance is all that matters. Try to improve it the better you can do but do not use unsafe blocks. Provide the sample code with comments. {query}