Optimize MemoryExtensions SequenceEqual for T = char

[ahsonkhan]

One option could be to convert to Span<byte> using AsBytes for any T = blittable type and call the existing vectorized method:
https://github.com/dotnet/corefx/blob/master/src/System.Memory/src/System/SpanHelpers.byte.cs#L889

Alternatively, create a char specific implementation and add a type check.

cc @KrzysztofCwalina, @GrabYourPitchforks, @stephentoub, @jkotas, @benaadams

[jkotas]

One option could be to convert to Span using AsBytes for any T = blittable

Blittability does not imply that it is ok to compare the type as bytes. It would need to be done explicitly for the set of types that it is ok to do for.

all the existing vectorized method:

Yes, I think having just one vectorized implementation that operates on bytes would be a good idea. You would need to change the length argument to nuint to avoid issues with large memory blocks.