Hey everyone! I keep hearing about Span<T> for performance in .NET 6/7/8. When is it appropriate to use Span<T> over standard arrays or List<T>, and what are the limitations with async methods?

Span<T> is a ref struct allocated exclusively on the stack. It represents a contiguous memory slice with zero heap allocations. Use it for parsing strings (ReadOnlySpan<char>), buffer slicing, and hot loops. Because it is a ref struct, it cannot live across await yields or be stored in heap classes—use Memory<T> instead for async workflows!

Great explanation! For example, substring parsing with string.Substring() creates a new heap string every time, while str.AsSpan().Slice(0, 5) creates zero allocations. Huge win for string-heavy parsers!