Please Add BinaryFormatter (a fast and secure one)

[tebeco]

It seems that the release of .Net 5 would need a fast and secure BinaryFormatter
https://github.com/dotnet/corefx/issues/38760#issuecomment-504539915

This repo look like the perfect one

[terrajobst]

I believe this should be closed. @benaadams already added all the secure aspects of BinaryFormatter to this code base.

[terrajobst]

@dotnet-bot please close this issue.

[tebeco]

it seems i cannot type properly ...