StartupCache

StartupCache is a replacement for Fastload.

It is meant to reside in the profile directory and provide a convient API to store continious chunks of data in it.

I think we can use the JAR format for this

Things I want:

• Index of entries in the file(at the end of it)
• Per entry-checksum like jars
• No multiplexing, writing to the cache will write into a memory buffer and it will be serialized on .Close()
• Single mmaped cache file to reduce file io
• Will be suitable for everything that's currently stored in fastload + manifest cache + pref cache + etc
• Cache should have a string table that cache's consumers can share.

Cache's filename should be:

startup.<endianness>.<wordsize>.cache to avoid issues with people moving profiles between machines