I previously avoided this due to being unsure of the effects; however, it's clear that we already use typed properties on Threaded things in other places anyway, and the only known issues are with uninit properties, and arrays.
the compressor used by RakLibInterface when opening a session is still
hardcoded, but that's because we have no way to select the correct
compressor at that point in the login sequence, since we aren't
propagating the protocol information up from RakLib right now.
