[C#] fastest byte[] to Hex string array

 public static class IOExt
    {
        private static readonly uint[] _lookup32Unsafe = CreateLookup32Unsafe();

        private static unsafe readonly uint* _lookup32UnsafeP = (uint*)GCHandle.Alloc(_lookup32Unsafe,GCHandleType.Pinned).AddrOfPinnedObject();

        private static uint [ ] CreateLookup32Unsafe()
        {
            var result = new uint[256];
            for ( int i = 0 ; i < 256 ; i++ )
            {
                string s=i.ToString("X2");
                if ( BitConverter.IsLittleEndian )
                    result [ i ] = ( ( uint )s [ 0 ] ) + ( ( uint )s [ 1 ] << 16 );
                else
                    result [ i ] = ( ( uint )s [ 1 ] ) + ( ( uint )s [ 0 ] << 16 );
            }
            return result;
        }

        public static string ByteArrayToHexViaLookup32Unsafe( byte [ ] bytes )
        {
            unsafe
            {
                var lookupP = _lookup32UnsafeP;
                var result = new char[bytes.Length * 2];
                fixed ( byte* bytesP = bytes )
                fixed ( char* resultP = result )
                {
                    uint* resultP2 = (uint*)resultP;
                    for ( int i = 0 ; i < bytes.Length ; i++ )
                    {
                        resultP2 [ i ] = lookupP [ bytesP [ i ] ];
                    }
                }
                return new string( result );
            }
        }

    }

https://stackoverflow.com/a/24343727/6127030