public int WithReturnAndSpanMarshalFieldPInvoke()
 {
     return(PInvoke.WithReturnAndSpanMarshal(_buff));
 }
        public int WithReturnAndSpanMarshalLocalBufferPInvoke()
        {
            Span <byte> buff = new byte[5];

            return(PInvoke.WithReturnAndSpanMarshal(buff));
        }