byte2hex

        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]
        private static char HexDigit(int p)
        {
            if (p < 10) return (char)(48 + p);
            return (char)(87 + p);
        }

        public static string ToHexString(this byte[] ba)
        {
            char[] digits = new char[ba.Length * 2];
            for (int i = 0; i < ba.Length; ++i)
            {
                int v = ba[i];
                digits[i + i] = HexDigit(v >> 4);
                digits[i + i + 1] = HexDigit(v & 0xF);
            }
            return new string(digits);
        }