System.Uri.ParseScheme C# (CSharp) Method

        private static unsafe ParsingError ParseScheme(string uriString, ref Flags flags, ref UriParser syntax)
        {
            int length = uriString.Length;
            if (length == 0)
                return ParsingError.EmptyUriString;

            if (length >= c_MaxUriBufferSize)
                return ParsingError.SizeLimit;

            //STEP1: parse scheme, lookup this Uri Syntax or create one using UnknownV1SyntaxFlags uri syntax template
            fixed (char* pUriString = uriString)
            {
                ParsingError err = ParsingError.None;
                ushort idx = ParseSchemeCheckImplicitFile(pUriString, (ushort)length, ref err, ref flags, ref syntax);

                if (err != ParsingError.None)
                    return err;

                flags |= (Flags)idx;
            }
            return ParsingError.None;
        }