prop140/compression: Refactor "directory request" code
Our current notion of "what is a directory request" includes a bunch of fields that are strewn around directory connections and passed to different functions. It would be nice to instead have a "directory request" type that we created and passed around as appropriate. This would make it easier to test our request generation/parsing code.
To upload designs, you'll need to enable LFS and have admin enable hashed storage. More information