As far as I'm aware, it's the development of Kestrel which pushed the introduction of ref/Span etc. Due to it Kestrel has seen quite a large speedup, it being o

As far as I'm aware, it's the development of Kestrel which pushed the introduction of ref/Span etc. Due to it Kestrel has seen quite a large speedup, it being one of the fastest HTTP servers nowadays. ref/Span allowed them to make the core almost allocation free, together with using vectorized operations (SIMD ) for parsing the request.