If you process strings heavily, Span<T> is a silent performance killer… in a good way. ReadOnlySpan<char> input = “order:12345”.AsSpan(); var idPart = input.Slice(input.IndexOf(‘:’) + 1); int id = int.Parse(idPart); Why this is powerful: No substring allocations No temporary strings Works directly on memory When to use it:Parsing, slicing, validation, protocol handling. When NOT to:Async methods […]