by Stan Drapkin
Uses SIMD acceleration for up to 32x speed-up.
///Xor's left byte span into dest byte span.
public static void Xor(Span<byte> dest, ReadOnlySpan<byte> left)
///Xor's left and right byte spans into dest byte span.
public static void Xor(Span<byte> dest, ReadOnlySpan<byte> left, ReadOnlySpan<byte> right)